implement a whitelist setting that - if populated - will only allow
specific IPs/hostnames to provide custom REMOTE_HOST_HEADERS header
values (i.e., `HTTP_X_FORWARDED_FOR`)
see: #6538
* Add separate Django app for configuration: awx.conf.
* Migrate from existing main.TowerSettings model to conf.Setting.
* Add settings wrapper to allow get/set/del via django.conf.settings.
* Update existing references to tower_settings to use django.conf.settings.
* Add a settings registry to allow for each Django app to register configurable settings.
* Support setting validation and conversion using Django REST Framework fields.
* Add /api/v1/settings/ to display a list of setting categories.
* Add /api/v1/settings/<slug>/ to display all settings in a category as a single object.
* Allow PUT/PATCH to update setting singleton, DELETE to reset to defaults.
* Add "all" category to display all settings across categories.
* Add "changed" category to display only settings configured in the database.
* Support per-user settings via "user" category (/api/v1/settings/user/).
* Support defaults for user settings via "user-defaults" category (/api/v1/settings/user-defaults/).
* Update serializer metadata to support category, category_slug and placeholder on OPTIONS responses.
* Update serializer metadata to handle child fields of a list/dict.
* Hide raw data form in browsable API for OPTIONS and DELETE.
* Combine existing licensing code into single "TaskEnhancer" class.
* Move license helper functions from awx.api.license into awx.conf.license.
* Update /api/v1/config/ to read/verify/update license using TaskEnhancer and settings wrapper.
* Add support for caching settings accessed via settings wrapper.
* Invalidate cached settings when Setting model changes or is deleted.
* Preload all database settings into cache on first access via settings wrapper.
* Add support for read-only settings than can update their value depending on other settings.
* Use setting_changed signal whenever a setting changes.
* Register configurable authentication, jobs, system and ui settings.
* Register configurable LDAP, RADIUS and social auth settings.
* Add custom fields and validators for URL, LDAP, RADIUS and social auth settings.
* Rewrite existing validator for Credential ssh_private_key to support validating private keys, certs or combinations of both.
* Get all unit/functional tests working with above changes.
* Add "migrate_to_database_settings" command to determine settings to be migrated into the database and comment them out when set in Python settings files.
* Add support for migrating license key from file to database.
* Remove database-configuable settings from local_settings.py example files.
* Update setup role to no longer install files for database-configurable settings.
f 94ff6ee More settings work.
f af4c4e0 Even more db settings stuff.
f 96ea9c0 More settings, attempt at singleton serializer for settings.
f 937c760 More work on singleton/category views in API, add code to comment out settings in Python files, work on command to migrate settings to database.
f 425b0d3 Minor fixes for sprint demo.
f ea402a4 Add support for read-only settings, cleanup license engine, get license support working with DB settings.
f ec289e4 Rename migration, minor fixmes, update setup role.
f 603640b Rewrite key/cert validator, finish adding social auth fields, hook up signals for setting_changed, use None to imply a setting is not set.
f 67d1b5a Get functional/unit tests passing.
f 2919b62 Flake8 fixes.
f e62f421 Add redbaron to requirements, get file to database migration working (except for license).
f c564508 Add support for migrating license file.
f 982f767 Add support for regex in social map fields.
* 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.
