The NodeEvaluation makes it difficult to use a course node in the
learning path access concept. So it is refactored to a minimum extent,
so that it can covering the previous functionality.
As a replacement a new security callback and a new tree node type is
introduced.

Move the functions of OlatRootFile and OlatRootFolder to the Local
implementations to simplify the use of VFS, implements factory methods
in VFSManager, reduce the number of call to meta informations in folder
listing

OO-2967: refactor the list of assessed identities in assessment tools to be delivered by the resource or the course element them self

OO-2897: implement last modification per user role (as participant or as coach), aggregate the values on structure nodes

OO-2790: add the options to upload assessment documents on a per course element / user base which behave like the user comment

OO-1761: more fix to the copy of course element within a course, copy or import of a course with a project broker element