Remove support of catalogue schema version 13.0
Catalogue schema version 13.0 is broken:
This bug has been fixed on the next version, 14.0.
CTA @ CERN has already been migrated to the catalogue schema version 14.0. For the public release we want users to migrate directly from version 12.0 to 14.0. One way to guarantee this is to remove the migration scripts of version 13.0.