Improvements to initial setup for developers

[alanshaw]

Fallout from #471

• Clean up docker containers properly. When my configuration was not setup properly containers weren't being cleaned up. This needs to be fixed.
  • In pw-test.config.cjs, if we throw in beforeTests then afterTests is not run
• Document somewhere that docker needs 8GB RAM for the postgres and postgrest docker containers to run in. I got "error 137" starting postgrest - this is because I only allowed 2GB of RAM for docker (I think maybe the default).
• Rename env vars (suggestions shown...). These are currently very generic and there was no documentation for the values they should contain:
  • DATABASE_URL => POSTGREST_API_URL
  • DATABASE_TOKEN => POSTGREST_BASIC_AUTH_TOKEN
  • DATABASE_CONNECTION => POSTGRES_CONN_STRING
• Add an npm script to setup a localtunnel for using local postgrest - the app needs to access a locally running database (or perhaps we should recommend setting up a free supabase account for this?).