XWIKI-20616: Update jstree files and remove reference to throbber.gif

`jstree` less files included in `xwiki-platform-tree-webjar` were coming from version `3.3.5` (or earlier) whereas the version declared in `pom.xml` is `3.3.16`.
This commit resynchronize files originated from `jstree` to match the ones provided in version `3.3.16`.

This commit also comment out the reference to `throbber.gif` in `jstree` `mixins.less` file as the gif file is no part of `xwiki-platform-tree-webjar` and rule is override in `tree.less` to use `spinner.gif`.

xwiki-platform-core/xwiki-platform-tree/xwiki-platform-tree-webjar/src/main/less/jstree/base.less

 // base jstree
 .jstree-node, .jstree-children, .jstree-container-ul { display:block; margin:0; padding:0; list-style-type:none; list-style-image:none; }
 .jstree-node { white-space:nowrap; }
-.jstree-anchor { display:inline-block; white-space:nowrap; padding:0 4px 0 1px; margin:0; vertical-align:top; }
+.jstree-anchor { display:inline-block; color:black; white-space:nowrap; padding:0 4px 0 1px; margin:0; vertical-align:top; }
 .jstree-anchor:focus { outline:0; }
-.jstree-anchor, .jstree-anchor:link, .jstree-anchor:visited, .jstree-anchor:hover, .jstree-anchor:active { text-decoration:none; }
-.jstree-icon { color:@text-color; display:inline-block; text-decoration:none; margin:0; padding:0; vertical-align:top; text-align:center; }
+.jstree-anchor, .jstree-anchor:link, .jstree-anchor:visited, .jstree-anchor:hover, .jstree-anchor:active { text-decoration:none; color:inherit; }
+.jstree-icon { display:inline-block; text-decoration:none; margin:0; padding:0; vertical-align:top; text-align:center; }
 .jstree-icon:empty { display:inline-block; text-decoration:none; margin:0; padding:0; vertical-align:top; text-align:center; }
 .jstree-ocl { cursor:pointer; }
 .jstree-leaf > .jstree-ocl { cursor:default; }
@@ -16,34 +16,6 @@
 .jstree-anchor > .jstree-themeicon-hidden { display:none; }
 .jstree-hidden, .jstree-node.jstree-hidden { display:none; }
 
-.jstree-no-links {
-  .jstree-anchor:focus {
-    outline: 0;
-  }
-  .jstree-anchor,
-  .jstree-anchor:link,
-  .jstree-anchor:visited,
-  .jstree-anchor:hover,
-  .jstree-anchor:active {
-    color: inherit;
-    text-decoration: none;
-  }
-}
-
-.jstree-no-link {
-  &.jstree-anchor:focus {
-    outline: 0;
-  }
-  &.jstree-anchor,
-  &.jstree-anchor:link,
-  &.jstree-anchor:visited,
-  &.jstree-anchor:hover,
-  &.jstree-anchor:active {
-    color: inherit;
-    text-decoration: none;
-  }
-}
-
 // base jstree rtl
 .jstree-rtl {
 	.jstree-anchor { padding:0 1px 0 4px; }
@@ -66,6 +38,7 @@
 .jstree-contextmenu .jstree-anchor {
 	-webkit-user-select: none; /* disable selection/Copy of UIWebView */
 	-webkit-touch-callout: none; /* disable the IOS popup when long-press on a link */
+	user-select: none;
 }
 .vakata-context {
 	display:none;
@@ -81,6 +54,7 @@
 		}
 		> a:focus { outline:0; }
 	}
+	.vakata-context-no-icons { margin-left:0; }
 	.vakata-context-hover > a { position:relative; background-color:#e8eff7; box-shadow:0 0 2px #0a6aa1; }
 	.vakata-context-separator {
 		> a, > a:hover { background:white; border:0; border-top:1px solid #e2e3e3; height:1px; min-height:1px; max-height:1px; padding:0; margin:0 0 0 2.4em; border-left:1px solid #e0e0e0; text-shadow:0 0 0 transparent; box-shadow:0 0 0 transparent; border-radius:0; }

xwiki-platform-core/xwiki-platform-tree/xwiki-platform-tree-webjar/src/main/less/jstree/main.less

@@ -4,15 +4,15 @@
 	.jstree-anchor,
 	.jstree-animated,
 	.jstree-wholerow { transition:background-color 0.15s, box-shadow 0.15s; }
-	.jstree-hovered { background:@hovered-bg-color; border-radius:3px; box-shadow:inset 0 0 1px @hovered-shadow-color; }
-	.jstree-context { background:@hovered-bg-color; border-radius:3px; box-shadow:inset 0 0 1px @hovered-shadow-color; }
-	.jstree-clicked { background:@clicked-bg-color; border-radius:3px; box-shadow:inset 0 0 1px @clicked-shadow-color; }
+	.jstree-hovered { background:@hovered-bg-color; border-radius:2px; box-shadow:inset 0 0 1px @hovered-shadow-color; }
+	.jstree-context { background:@hovered-bg-color; border-radius:2px; box-shadow:inset 0 0 1px @hovered-shadow-color; }
+	.jstree-clicked { background:@clicked-bg-color; border-radius:2px; box-shadow:inset 0 0 1px @clicked-shadow-color; }
 	.jstree-no-icons .jstree-anchor > .jstree-themeicon { display:none; }
 	.jstree-disabled {
-		background:transparent; color:@disabled-color; opacity:@disabled-opacity;
+		background:transparent; color:@disabled-color;
 		&.jstree-hovered { background:transparent; box-shadow:none; }
 		&.jstree-clicked { background:@disabled-bg-color; }
-		> .jstree-icon { filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'jstree-grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#jstree-grayscale"); /* Firefox 10+ */ filter: gray; /* IE6-9 */ -webkit-filter: grayscale(100%); /* Chrome 19+ & Safari 6+ */ }
+		> .jstree-icon { opacity:0.8; filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'jstree-grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#jstree-grayscale"); /* Firefox 10+ */ filter: gray; /* IE6-9 */ -webkit-filter: grayscale(100%); /* Chrome 19+ & Safari 6+ */ }
 	}
 	// search
 	.jstree-search { font-style:italic; color:@search-result-color; font-weight:bold; }
@@ -43,17 +43,17 @@
 .jstree-@{theme-name} {
 	.jstree-theme(24px, "@{image-path}32px.png", 32px);
 	&.jstree-rtl .jstree-node { background-image:url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAACAQMAAAB49I5GAAAABlBMVEUAAAAdHRvEkCwcAAAAAXRSTlMAQObYZgAAAAxJREFUCNdjAAMOBgAAGAAJMwQHdQAAAABJRU5ErkJggg=="); }
-	&.jstree-rtl .jstree-last { background:transparent; }
+	&.jstree-rtl .jstree-last { background-image:none;  }
 }
 .jstree-@{theme-name}-small {
 	.jstree-theme(18px, "@{image-path}32px.png", 32px);
 	&.jstree-rtl .jstree-node { background-image:url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAACAQMAAABv1h6PAAAABlBMVEUAAAAdHRvEkCwcAAAAAXRSTlMAQObYZgAAAAxJREFUCNdjAAMHBgAAiABBI4gz9AAAAABJRU5ErkJggg=="); }
-	&.jstree-rtl .jstree-last { background:transparent; }
+	&.jstree-rtl .jstree-last { background-image:none;  }
 }
 .jstree-@{theme-name}-large {
 	.jstree-theme(32px, "@{image-path}32px.png", 32px);
 	&.jstree-rtl .jstree-node { background-image:url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAACAQMAAAAD0EyKAAAABlBMVEUAAAAdHRvEkCwcAAAAAXRSTlMAQObYZgAAAAxJREFUCNdjgIIGBgABCgCBvVLXcAAAAABJRU5ErkJggg=="); }
-	&.jstree-rtl .jstree-last { background:transparent; }
+	&.jstree-rtl .jstree-last { background-image:none;  }
 }
 
 // mobile theme attempt

xwiki-platform-core/xwiki-platform-tree/xwiki-platform-tree-webjar/src/main/less/jstree/mixins.less

@@ -17,7 +17,7 @@
 	.jstree-node,
 	.jstree-icon { background-image:url("@{image}"); }
 	.jstree-node { background-position:-(@image-height * 9 + @correction) -@correction; background-repeat:repeat-y; }
-	.jstree-last { background:transparent; }
+	.jstree-last { background-image:none; }
 
 	.jstree-open > .jstree-ocl { background-position:-(@image-height * 4 + @correction) -@correction; }
 	.jstree-closed > .jstree-ocl { background-position:-(@image-height * 3 + @correction) -@correction; }
@@ -67,7 +67,7 @@
 
 	&.jstree-rtl {
 		.jstree-node { background-image:url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAACAQMAAAB49I5GAAAABlBMVEUAAAAdHRvEkCwcAAAAAXRSTlMAQObYZgAAAAxJREFUCNdjAAMOBgAAGAAJMwQHdQAAAABJRU5ErkJggg=="); background-position: 100% 1px; background-repeat:repeat-y; }
-		.jstree-last { background:transparent; }
+		.jstree-last { background-image:none; }
 		.jstree-open > .jstree-ocl { background-position:-(@image-height * 4 + @correction) -(@image-height * 1 + @correction); }
 		.jstree-closed > .jstree-ocl { background-position:-(@image-height * 3 + @correction) -(@image-height * 1 + @correction); }
 		.jstree-leaf > .jstree-ocl { background-position:-(@image-height * 2 + @correction) -(@image-height * 1 + @correction); }
@@ -80,7 +80,8 @@
 	}
 	.jstree-themeicon-custom { background-color:transparent; background-image:none; background-position:0 0; }
 
-	> .jstree-container-ul .jstree-loading > .jstree-ocl { background:url("@{image-path}throbber.gif") center center no-repeat; }
+	// This line is commented out compared to upstream source as throbber.gif is not available in xwiki-platofrm-tree-webjar and this style is override in tree.less to use spinner.gif.
+	//> .jstree-container-ul .jstree-loading > .jstree-ocl { background:url("@{image-path}throbber.gif") center center no-repeat; }
 
 	.jstree-file { background:url("@{image}") -(@image-height * 3 + @correction) -(@image-height * 2 + @correction) no-repeat; }
 	.jstree-folder { background:url("@{image}") -(@image-height * 8 + @correction) -(@correction) no-repeat; }
@@ -101,5 +102,4 @@
 	.jstree-ellipsis { overflow: hidden; }
 	// base height + PADDINGS!
 	.jstree-ellipsis .jstree-anchor { width: calc(100% ~"-" (@base-height + 5px)); text-overflow: ellipsis; overflow: hidden; }
-	.jstree-ellipsis.jstree-no-icons .jstree-anchor { width: calc(100% ~"-" 5px); }
 }

xwiki-platform-core/xwiki-platform-tree/xwiki-platform-tree-webjar/src/main/less/jstree/responsive.less

@@ -51,7 +51,7 @@
 	.jstree-checkbox { background-image:url("@{image-path}@{base-height}.png"); background-size:(@base-height * 3) (@base-height * 6); }
 
 	.jstree-node { background-position:-(@base-height * 2) 0; background-repeat:repeat-y; }
-	.jstree-last { background:transparent; }
+	.jstree-last { background-image:none; }
 	.jstree-leaf > .jstree-ocl { background-position:-(@base-height * 1) -(@base-height * 3); }
 	.jstree-last > .jstree-ocl { background-position:-(@base-height * 1) -(@base-height * 4); }
 	/*