The set make dependencies between mm and other services cleaner,
in particular, after the set:
- the query processor no longer needs migration manager
(which doesn't need query processor either)
- the database no longer needs migration manager, thus the mutual
dependency between these two is dropped, only migration manager
-> database is left
- the migration manager -> storage_service dependency is relaxed,
one more patchset will be needed to remove it, thus dropping one
more mutual dependency between them, only the storage_service
-> migration manager will be left
- the migration manager is stopped on drain, but several more
services need it on stop, thus causing use after free problems,
in particular there's a caught bug when view builder crashes
when unregistering from notifier list on stop. Fixed.
Tests: unit(dev)
Fixes: #5404
36d90e637e