[Datalayer] Add base project

[kylestang]

Description

This PR is built on top of #100, make sure to merge that first Adds the datalayer base project and docker configuration. Sets up pgbouncer to connect to the database, and builds a rust executable which is copied into the datalayer.

Closes #25

How to Test

docker compose up --build

psql -p 8300 -U martletplace -h localhost

Checklist

• [x] The code includes tests if relevant
• [x] I have actually self-reviewed my changes and done QA