want database schema validator

[davepacheco]

We could catch issues like #1533. More generally, we could validate:

• names, types, nullability, and uniqueness for standard fields (like id, name, time_created, time_modified, time_deleted)
• uniqueness of indexes (see some non-unique indexes in dbinit.sql are fishy #1497 -- unclear if this could be a hard rule)
• singular vs plural?
• snake case vs. camel case?