Social auth and SSO updates:

* Move auth backends into sso app.
* Add support for mapping social auth users into organizations and teams.
* Return social auth backends in a consistent order in the API.
* Remove custom SAML attribute mapping and use options provided by PSA.
* Add pipeline function to raise an exception if no user has been found or created; added comments on how to disable new user creation.
* Add comments for defining a custom social auth pipeline function.

awx/main/tests/base.py

@@ -28,11 +28,11 @@ from django.test.utils import override_settings
 
 # AWX
 from awx.main.models import * # noqa
-from awx.main.backend import LDAPSettings
 from awx.main.management.commands.run_callback_receiver import CallbackReceiver
 from awx.main.management.commands.run_task_system import run_taskmanager
 from awx.main.utils import get_ansible_version
 from awx.main.task_engine import TaskEngager as LicenseWriter
+from awx.sso.backends import LDAPSettings
 
 TEST_PLAYBOOK = '''- hosts: mygroup
   gather_facts: false