Changed the on content load direct method call to event

This change allow extending the on content load easly.
fixes #3274 moved config template to the new two-pane and add full screen editing
fixes #3140 - API to allow importing of puppet classes
fixes #3312 - support /users/extlogin as a login page based on REMOTE_USER.
fixes #3312 - support logout from REMOTE_USER-based logons.
fixes #3312 - when authorize_login_delegation_auth_source_user_autocreate is set, creates the unknown authenticated user.
fixes #3312 - tweaking nil tests; private.
fixes #3312 - add tests.