Run commands on coordinator

I haven't tested this yet, but I believe the code is more or less ready by now!

This makes sure that commands required to run on `device.group.coordinator` always does so.

There's probably lots of ways to optimize this, I just wanted to write down the idea of it to begin with.
@KennethNielsen it seems like your correct, it was added in a earlier version of the decorator, whether it was actually then or not, it at least seems to work without now!