fixing bug #5668 Message incorrect lors d'un défaut de login lié au domaine de connexion
Bug #5997: fixing some problems
- refactoring the code
- using centralized treatments around WYSISYG (WysiwygController)
- adding a transformer class for WYSISYG
- adding unit test on new tools
- adding new method on URLManager to provide anywhere in the code the server URL
Bug #5668 : fixing a NullPointerException
Merge branch 'bug-5668' into core-5.14.x