Get it to compile on my machine
Add pgsql IDL
Started on actual extension
Stub impl of Postgres extension
Add Postgres to CMake
Adds initial result fetching.

This also moves the state of development into "usable - just",
since you can now actually do basic database stuff.
Improve field name conversion message
Add affected_rows
Add extra paths to PGSQL cmake file
Handle connection failures in pgconnect