This reverts commit 5d55a60e.

We need the device list to be refresh as soon as possible, since we
might need it during initialize()

So its schema matches what we expect during the sanity checks

The triggers don't kick in when dropping the table so the FTS table was
still containing the previous values, causing all subsequent insertions
to fail.
Fix #137

Due to a mismatch between the meaning of "default" between
"addRequestJoin" and "orderBy"

So the app can clear the database and try to keep the playlists if an
error is detected

refs #121

We were refusing to link the same mrl to multiple entities. For
instance, the same media in 2 playlist files would have yielded a
constraint failure.

This way we can fetch the schema for the backup table during migrations

If the selection request was failing, the Task_backup table was left
behind

Which we will use to reload a specific playlist, based on its MRL
refs #121

That we can use to dump our playlist backups

Since it will create non-thumbnail folder(s) starting from next commit

We will soon need to create more files than just thumbnails

ie. internal & external media