Ref T1191. Some notes here:
- Drops the old LDAP and OAuth info tables. These were migrated to the ExternalAccount table a very long time ago.
- Separates surplus/missing keys from other types of surplus/missing things. In the long run, my plan is to have only two notice levels:
- Error: something we can't fix (missing database, table, or column; overlong key).
- Warning: something we can fix (surplus anything, missing key, bad column type, bad key columns, bad uniqueness, bad collation or charset).
- For now, retaining three levels is helpful in generating all the expected scheamta.