Add next.jdbc result set builders

[arichiardi]

The set of options that you can pass to next.jdbc is very powerful.

It allows row/column name manipulation without post processing the result.

Describe the solution you'd like
Given the pod nature of this wrapper, I seem to have understood that we cannot pass functions like :builder-fn in. The next best thing might be passing symbols that the pod resolves to functions.

Describe alternatives you've considered
Post-processing the result is an option. Also, every time the api diverges I doubt the value of keeping it compatible (and maintaining it in case of future breakage). So I would be ok with a "maybe not" answer to this feature request.

[borkdude]

@arichiardi Just as a piece of feedback, which database are you using?

[arichiardi]

Postgres at the moment.