Enable non-docker postgres

[ballPointPenguin]

utilize docker compose --profile postgres, and POSTGRES_DOCKER var,
to enable/disable using dockerized postgres.

For using docker compose directly

Now, by default, docker compose ... will NOT run a dockerized postgres service. You must provide a valid DATABASE_URL in your environment.
To continue using the dockerized postgres service, all docker compose commands must include the flag --profile postgres

For using make

The Makefile will read POSTGRES_DOCKER in your env file. If it is false, it will not include the postgres docker service. However, if POSTGRES_DOCKER=true (defaults to true if unset), then make will run as before, including postgres docker service (via --profile postgres) in all of its actions.

TL;DR

To disable docker postgres, include POSTGRES_DOCKER=false in your .env (or prod.env).

To keep using docker postgres, do nothing (if using make), or amend any docker compose calls with --profile postgres.

Closes #1749 and #1751

[ballPointPenguin]

Prior to #1816, the Github actions are expected to fail