Registration Documentation Should Handle Production and Container Deployments

The current documentation about registration is too focused on the development/trial scenario. It requires manual steps and direct access to the Nuxeo Server instance. This is not viable in at least two scenarios: production deployments and container-based deployments.

For Production deployments it doesn't make sense to require the customer to directly access the production system in order to register it. There should be no real-time dependency, when deploying a production system, on registration. I.e. what if registration fails because Connect is offline? The registration needs to be taken care before the production system is ever deployed. This applies to the registration instructions found here:

https://doc.nuxeo.com/n/ye1

For the Docker scenario, the instructions related to registration here should just be removed:

https://doc.nuxeo.com/nxdoc/setting-up-your-nuxeo-environment/#installation

I don't think anyone every uses Docker this way. I.e. if using `docker-compose`, you need the CLID before ever launching the instance. Manually launching a container just to create a CLID is cumbersome, and you need to extract the CLID from the container when finished.

In both scenarios there is a viable solution: you can create a CLID using Nuxeo Connect without any access to Nuxeo Server.

To be clear about the general goal here: the goal is to provide a more professional presentation of the registration experience, aimed and real customer deployments, not test/development scenarios.