Manage multiple Compose files

[king-alexander]

The Admiral's development composition exposes a bash shell which runs the script to collect new certificates, but it would be bad practice to deploy the composition for this sole purpose. Therefore we need to manage the complexity of multiple Compose files, whether that be incorporating override options, merging the Compose files, or some other solution.

Per the discussion with @mcdonnnj in cisagov/ansible-role-admiral#3 (comment)