Application configuration can be provisioned:
- through environment
- through a configuration file
The current image uses environment, which is good, but actually use it
to create a configuration file (which is rather bad, as it's not comprehensive).
Ideally, we should strive to allow Etherpad to directly parse environment,
but this isn't a current upstream goal.
So, to provision a comprehensive settings.json through rOPS is probably
better than tweak environment to recreate such a file each container start.
The implementation is straightforward: bypass the entrypoint,
ie don't check anymore if connection works and don't provision a settings.json.
Node so starts directly.