- Define sitepolicy handler manager class, base class and the core handler
- Allow to set a plugin as sitepolicyhandler that implements the sitepolicy API
- Modify web services to return information from the 3rd party handler instead of core if needed
This legacy polyfill allows plugin developers who release a single
branch to work with multiple versions of Moodle to support the API in
both Moodle 3.3 with PHP 5.6, and later versions.
