add round trip testing for all column types (postgres module)

[bertlebee]

This should use zio-sql to insert values into the database, then read them back out, and ensure they're the same as the ones that went in.

This is dependent on InsertModule.

[sviezypan]

Types that we are inserting to db and types that we are reading back are depending on the description of the table. If metamodel is wrongly defined, inserts and read fail at runtime. @robmwalsh Can you please clarify what this would test?