* refactor run automated backup
* new backup status of Queued
* adhoc task for backing up a course
* course locking for course backup adhoc task
* use Moodle locking instead of custom locking for run automated backup task
* add unit tests to extracted methods
Specially noticeable under Windows, where some resources/files
are kept open/busy/locked, causing all sort of problems, easily
detectable in phpunit resets.
This patch adds asynchronous backup and restore functionality
to Moodle. This is an optional feature and is not enabled by
default. It can be enabled by site administrators.
Asynchronous backup and restores are actioned by the Moodle
adhoc task API. The progress of backup and restores is
displayedin the Moodle UI. Users can also be sent a message
when a backup or restore operation completes via the
Moodle messaging API.