ECMS-4181: UnsupportedRepositoryOperationException when publishing an image

Fix description:
* Disable Publish, Aprove, RequestApproval buttons for webcontent's subnode.
ECMS-4724: MyDraftContent: unexpected behavior when clicking on a content in this list.

Fix description:
   - the space in the path was escaped as %20. We need to unescape the space in the path
ECMS-4667 NPE when using File explorer portlet

Problem analysis:
* getUserFavoriteFolder(String userName) allows to return a null object "Node".
  However when this method is invoked, there isn't any check whether the result is null or not.

Fix description:
* Verify the result of getUserFavoriteFolder before accessing its value.
ECMS-3615: Insert Content Link uses absolute path

Fix description:
* Remove hostname and using relative path when insert content.