Use an opt-out flow for comments in video, springify notifications and
notifications handlers

Open the preview folder in a new bread crumb instead of a modal dialog
to allow opening viewer and editor in full screen mode.

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.

Transfer metadata by copy / upload / download of zip files, unify copy
of streams, copy metadata during copy of courses, remove backwards
compatibility mode for import

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

of administrator role in organisation tree, enhance UI in user
management and fix some permission issues to edit invitee and guest,
remove admin by-pass for the full text search...

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

OO-848: enhance the interface of course nodes to do a post copy processing different from the import one

OO-990: rework importation of course node with references, implement autowiring capabilities in controllers