Allow additional arguments to be used during type map lookups

Determining things like precision and scale in postgresql will require
the given blocks to take additional arguments besides the OID.

- Adds the ability to handle additional arguments to `TypeMap`
- Passes the column type to blocks when looking up PG types
Merge pull request #15248 from sgrif/sg-additional-type-map-args

Allow additional arguments to be used during type map lookups