XWIKI-12206: Add the support of nested spaces in the REST API.

xwiki-platform-core/pom.xml

...-core/xwiki-platform-rest/xwiki-platform-rest-api/pom.xml

...esources/attachments/AttachmentAtPageVersionResource.java

...rest/resources/attachments/AttachmentHistoryResource.java

.../xwiki/rest/resources/attachments/AttachmentResource.java

...rest/resources/attachments/AttachmentVersionResource.java

...sources/attachments/AttachmentsAtPageVersionResource.java

...xwiki/rest/resources/attachments/AttachmentsResource.java

...va/org/xwiki/rest/resources/comments/CommentResource.java

...xwiki/rest/resources/comments/CommentVersionResource.java

...a/org/xwiki/rest/resources/comments/CommentsResource.java

...wiki/rest/resources/comments/CommentsVersionResource.java

...i/rest/resources/objects/ObjectAtPageVersionResource.java

...ources/objects/ObjectPropertiesAtPageVersionResource.java

...wiki/rest/resources/objects/ObjectPropertiesResource.java

...esources/objects/ObjectPropertyAtPageVersionResource.java

.../xwiki/rest/resources/objects/ObjectPropertyResource.java

...java/org/xwiki/rest/resources/objects/ObjectResource.java

.../rest/resources/objects/ObjectsAtPageVersionResource.java

...i/rest/resources/objects/ObjectsForClassNameResource.java