feat(storage): add Route 53 backend (TXT records, base64-encoded items, the works)

Corey Quinn has created a PR that implements a backend for ExtendDB, AWS' DynamoDB compatible locally hosted alternative, using Route 53. That's Route53 the DNS service working as a database.

I do declare that Route 53 is in fact a database. I dare you to prove me wrong.

The only currently supported backend for ExtendDB is PostgreSQL.