MDL-70815 core_completion: Update completion_info

MDL-70815 core_completion: Update completion_info

* Update completion_info::get_data() to add other completion
information from a new method called get_other_cm_completion_data().
This allows the storage of the completion statuses of the following
completion rules to completion_info objects:
  - 'Students must receive a grade' completion rule.
  - Any custom completion rule defined by an activity.
This allows detailed completion information to be fetched for course
modules.
It also allows custom completion statuses to be cached which will help
reduce DB queries when fetching completion statuses.
* Update update_state() to fetch overall completion state from the
module's activity_custom_completion implementation. Falls back to the
*_get_completion_state() callback function.
* Update internal_set_data() to include the other cm completion data
in the updated cache data for the module instance.