Archive and Delete old Metabase Cache Database

[preaction]

Once we have migrated all the old Metabase cache data (#21), and removed all processes depending on the Metabase cache data (#22), we can delete the old Metabase cache data forever.

Just in case, we should create and store an archive of this database somewhere (probably on a hard drive in my house, so that by the time I lose that hard drive, we'll be sure that we don't need that data anymore). Making this into a SQL file using mysqldump is probably not a good idea, since this database contains compressed binary data, so we'll need some other way to store a backup of this data.