Migrate journal dbs files back to the sync folder

Migrate journal dbs files back to the sync folder

In case of past collisions during the 3.0 times... well one will resync
from scratch unfortunately. But if that happened there are likely other
problems which occurred.

Also this might fix some of the bugs with people loosing settings from
the database. Indeed the -wal and -shm concatenations were wrong. Using
append was in fact changing the folderDefinition member which (I guess)
would potentially lead to funny ".db-wal-shm-wal-shm" names.

Signed-off-by: Kevin Ottens <kevin.ottens@nextcloud.com>