move create channel icon to toolbar

packages/rocketchat-theme/client/imports/base.less

packages/rocketchat-theme/server/colors.less

packages/rocketchat-ui-sidenav/package.js

packages/rocketchat-ui-sidenav/side-nav/channels.coffee

packages/rocketchat-ui-sidenav/side-nav/channels.html

packages/rocketchat-ui-sidenav/side-nav/combined.coffee

packages/rocketchat-ui-sidenav/side-nav/combined.html

...s/rocketchat-ui-sidenav/side-nav/createChannelFlex.coffee

...ges/rocketchat-ui-sidenav/side-nav/createChannelFlex.html

.../rocketchat-ui-sidenav/side-nav/createCombinedFlex.coffee

...es/rocketchat-ui-sidenav/side-nav/createCombinedFlex.html

...ages/rocketchat-ui-sidenav/side-nav/directMessages.coffee

packages/rocketchat-ui-sidenav/side-nav/directMessages.html

.../rocketchat-ui-sidenav/side-nav/directMessagesFlex.coffee

...es/rocketchat-ui-sidenav/side-nav/directMessagesFlex.html

...es/rocketchat-ui-sidenav/side-nav/listCombinedFlex.coffee

...ages/rocketchat-ui-sidenav/side-nav/listCombinedFlex.html

...ocketchat-ui-sidenav/side-nav/listDirectMessagesFlex.html

.../rocketchat-ui-sidenav/side-nav/listDirectMessagesFlex.js

packages/rocketchat-ui-sidenav/side-nav/toolbar.html