Docker-based system services should require the Docker service

Summary

Our mighty Docker-based system services do not wait for the Docker service to start.

Steps to reproduce

Reboot a server with Docker-based services.

Expected behavior

First, Docker starts. Then, the Docker-based services start.

Actual behavior

Everything just starts and does not wait and it's a mess. Some services start before Docker is ready and they fail and never try again.

Possible fixes

Maybe set sth like:

service_requirements:
  - "docker.service"
service_order_after:
  - "docker.service"