MTN/ENH: Docker all the things

[CJ-Wright]

It might make life easier for us to make a Docker (or a couple Docker) instance where we store an active environment. We could have a separate Sim environment which holds some simulated data/beamline for showing our stuff off. The main benefit is that we can just point our users to the docker image. I think the correct analogy is that if using conda packages is like handing a person the pre-build copy of the software, docker is like handing the person a copy of your machine. This way we don't worry about what is where or which software is installed. @danielballan