UC-268: add hook for onSave Hibernate interceptor
UC-192: add preConfigProviders, if any exception occur then config won't be deployed / cfengine won't run
UC-1512: Phantom Users

- A phantom user can not have a phone registered against it and is used for the purposes of call routing.
- added new setting at user level to mark user as phantom
- added queries to count phantom users and load phantom users by page
- phantom user cannot register phones
- added user table filter to show phantom users
- new icon / text tooltip to indicate phantom user
UC-192: add mechanism to collect warnings and report them in admin UI