OO-3489, OO-3492, OO-3493, OO-3494, OO-3496, OO-3497: infrastructure to export user data, export  portraits, notes, personal folder, calendars, subscriptions, delete calendars after usser deletion

OO-3055: add new e-Assessment node in Administration, add a new document pool module, refactor the administration of taxonomy to separate the document pool features from the taxonomy itself, add an administration panl for the question pool

OO-3108: close the file system created for zip files, set default encoding to UTF-8 for some stream to string operations

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

OO-2575: better handle error during login with defective business path, fix NPE in artefact pool v1 if the portfolio v1 is disabled

OO-2479: reduce overhead everywhere, optimized and simplified query to count the participants of a group, bypass reloading the group set of identities, bypass reloading the base group of business group...

OO-2429: move the foreign key from identity to user, remove double mapping of identity, add more unit tests for invitation, unify the methods to create the user and identity

OO-2196: system-wide configuration for entry point in binder, new binder, new binder from template, new binder from course

OO-1593: rework the interaction behavior of the access rights controller for invitation, fix search invitation per identity, fix rs in invitee mode