Bug 1813986 - Add an asyncVacuum() method to storage async connections, and...

Bug 1813986 - Add an asyncVacuum() method to storage async connections, and let VacuumManager use it. r=asuth

Add asyncVacuum to mozIStorageAsyncConnection, that dispatches a runnable to
the helper thread, where it will execute a full or incremental vacuum, depending
on the connection auto_vacuum value.
It also supports vacuuming attached schemas.
asyncVacuum() supports changing both the page_size and auto_vacuum.
Change mozIStorageVacuumParticipant to return a mozIStorageAsyncConnection and
allow specifying whether incremental vacuum should be enabled.
Change vacuumManager notification from heavy-io-task to vacuum-begin and vacuum-end
since the original proposal of notifying heavy IO didn't take off.
Cleanup test_vacuum to be able to use instances of the test VacuumParticipant,
that means we can remove the no more necessary registerESM hack.
Fix Places History as the only cpp consumer.

Differential Revision: https://phabricator.services.mozilla.com/D168298