The index for message was fairly inefficient as it was only using the
cursor, as it was referring to the old `chat_id` field.
This meant that newer messages would be fetched much faster then older
messages.
The index has been changed so that now it includes `local_chat_id`
(which is currently used for filtering), and not using `hide`.
The reason being is that `hide` is a low cardinality index, so there's
no performance benefit to have it in, also it's mostly ignored by the
query planner.
This commit also adds the missing migrations, we generated the file, but
the source was missing, probably I forgot to add them in a rebase. They
have been generated from the migration file, using `RestoreAsset`.
Andrea Maria Piana