Support Docker secrets

Is your feature request related to a problem? Please describe.

• Currently the documentation states to use .env files / environment variables to pass secrets to run MonicaHQ with docker compose / docker. I would love to make use of docker secrets: https://docs.docker.com/compose/compose-file/compose-file-v3/#secrets instead of having secret things in my .env file.

Describe the solution you'd like Support docker secrets. Either by adding new environment variables such as DB_PASS_FILE which actually does a cat /run/secrets/DB_PASS_FILE inside the container - or we could have some logic that checks whether /run/secrets/DB_PASS exists and overwrites whatever is in environment variable DB_PASS.

Describe alternatives you've considered (optional) Have my secrets in the .env file