Review PR: Enhance PostgreSQL configuration support in the backend

[anvarknian]

Hi guys,
Can anyone help reviewing this PR: #4779

This PR includes:

1. Updated db.js to include PostgreSQL-specific connection options such as schema name and SSL mode.
2. Modified config.js to read new environment variables for PostgreSQL schema name and SSL mode.
3. Added PostgreSQL configuration section in knexfile.js.
4. Updated docker-compose.dev.yml and documentation to reflect new environment variables for PostgreSQL schema name and SSL mode.