Indicate in the side menu when you are running on the test network

[mplorentz]

Right now you have to go into the debug settings to see if you are running on the main network or the test network. It's easy to forget that you are running on the test network and think something is a bug when really it just doesn't work on the test network (for instance, joining a pub or room that runs on the main network).

If we add a little badge that says "Test Network" or something similar to the side menu (or somewhere else obvious) it will save us some time.