openolat#216: adding initial clearLearningPathIncompatibleSettings interface function to ICourseNodeCopyConfigurator

Login happens only with authentication informations, identity name is
now only used for legacy directory name. User name of authentication can
be changed. LDAP users can be imported with LDAP::ldapUid. Users can be
imported in courses, groups... with First name last name.

Implement a CSRF token to protect a little more against CSRF attack.
Enhance the UI framework to allow opening a link in a new browser
window.

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

openolat#95: check if the precondition is null before trying to replace the ids in the migration process

Prevent memory leak of portrait, reload the model, not the table, clean
up all controller...

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.