Service connections version

Don't merge this. For discussion purposes only.

I did a quick spike for what I think a service connections version of an
RSA client gem would look like.

Usage:

`FieldOfMembership::Match.fetch(addresses: [{state: 'NY', zip_code: 10001]}])`
this should happen in 
```
RSAAuthority::Signer.new(self, private_key, client_id).sign
```