=per #15131 Make LocalSnapshotStore fail if it can't create target directory
Merge pull request #15301 from akka/wip-15131-snapshotstore-directory-check-ban

=per #15131 Make LocalSnapshotStore fail if it can't create target directory
Merge pull request #15308 from ktoso/per-persistAsync-ktoso

+per #15227 persistAsync for PersistentProcessor
+per #15229 defer for PersistentActor

Deferred events are not persisted, thus will not participate in replays
etc. If users want events to be persisted, they can simply use
`persistAsync` instead.

Resolves #15229
Depends on #15227