x-rds Lookup/Use support

[JohnPreston]

As a developer I might already have created a database in production, outside of ComposeX.
I would like to be able to identify a pre-existing DB and its secret and associate it to my services.

Describe the solution you'd like

x-rds:
  dbA:
    Lookup:
      Tags:
         - key: Value
       Secret:
         Tags:
           - key: Value
         Name: "secret/name/in/secrets-manager"

Describe alternatives you've considered

x-rds:
  dbA:
    Lookup:
      Tags:
        - key: Value
    Secret:
      - dbasecret

secrets:
  dbasecret:
    x-secrets:
      Name: "secret/name/in/secrets-manager"

In the second syntax, we are re-using the docker-compose secrets and if associated to a DB we would automatically add it to the service definition.