Disable HEALTHCHECK and update supabase image

Issue: database-lab#533

Disable HEALTHCHECK inherited from the supabase image.

Fixed:

384b753d1dc7 registry.gitlab.com/postgres-ai/se-images/supabase:15 "docker-entrypoint.s…" 46 minutes ago Up 46 minutes (unhealthy) 5432/tcp, 127.0.0.1:6000->6000/tcp dblab_clone_6000

            "Health": {
                "Status": "unhealthy",
                "FailingStreak": 23,
                "Log": [
                    {
                        "Start": "2023-08-07T18:05:20.116152608Z",
                        "End": "2023-08-07T18:05:20.214898274Z",
                        "ExitCode": 2,
                        "Output": "localhost:5432 - no response\n"
                    },
                    {
                        "Start": "2023-08-07T18:05:22.222857195Z",
                        "End": "2023-08-07T18:05:22.320417567Z",
                        "ExitCode": 2,
                        "Output": "localhost:5432 - no response\n"
                    },

Additionally:

• Update supabase postgres image to version 15.1.0.112
• Install the pgdg repository. The latest releases of the supabase postgres image do not contain the postgres repository that we need to install the postgresql-plpython3-15 package.
• Added PG_MAJOR env (missing in the latest versions of supabase postgres image)