Support for Prepared and Procedural Statements

First, thanks for this amazing library.

Wondering if there are any plans on the roadmap to support prepared statements. Here's the documentation for Postgres, but I believe MySql and most DB's support it Postgres Prepared statements

I am also wondering if Procedural statements could be supported. I'm guessing this would have to be done in DB specific way. I think this fits in with the Custom Queries support, as sometimes I may want to leverage calling a PG/SQL function that contains Postgres logic that Beam doesn't yet support. One example is if I have Postgres with PGCrypto and I want to call a function that runs crypt