* Removes Add/Remove methods
* Publicise necessary fields and methods so we could extend it
* Publicise mock API
* More comments and additional simplifications
* Sync with master
Still having low coverage :/ - should be addressed in #17208
* incapsulates multipleldap logic under one module
* abstracts users upsert and get logic
* changes some of the text error messages and import sort sequence
* heavily refactors the LDAP module – LDAP module now only deals with LDAP related behaviour
* integrates affected auth_proxy module and their tests
* refactoring of the auth_proxy logic
Oleg Gaidarenko