OO-1593: return more informations on score evalutation, add a specific persistent assessable course node, fix selenium tests and unit tests

OO-770: work on status for portfolio, group task (indivudal variant), refactor the map of course node per identity...

OO-1744: queue the changes to the assessed identities list and make the changes with set instead of add/remove to hardened the list against changes coming from the user events and from JMS event

OO-1741 remove ? from dummy avatar images, adding anonymous avatar and removing old avatar images outside the theme

OO-1739: backport the delete button in file element and use it in user profil for the avatar, in the resource description and in the catalog entry editor

OO-1733: clean up all possible references, the check to prevent deletion must happen before reaching the delete method of the service

OO-1732: take the number of user properties to render the first row of headers in the test archive file

no-jira: beautify the list of sub levels in the catalog if the number of levels is uneven and the view of type list