Database connection, create db & tables, POST env
- Adds a connection to mariadb using environment variables DB_USER, DB_PASS, DB_DATABASE, DB_HOST
- Creates db and tables if they don't exist
- Adds the following routes:
- POST /environments - inserts environment details into db and returns environment object
- /healthz - returns 200 OK
- /ready - returns 200 OK if db ping succeeds
Bug: T346380