Make Docker-based workflows seamless #4028
Description
At the moment, we still require our workflows to invoke docker-up to even use Docker. This removes some of the benefits of having "less" to set-up on the workflow, since you still need to manually invoke docker-up everytime you want to work on a Docker project.
docker-up as much as possible should be invoked in the background instead of requiring the user to do it manually, since it doesn't make sense to call it from CLI when you expect Gitpod to do it for you.