Restructure AsyncIdle

[heuristicus]

Currently AsyncIdle has a mixture of uses and does quite a few different things depending on the state of various flags.

I don't really know the best way to do this, but perhaps starting by splitting the function up into separate functions handling each of the commands makes sense.

The variables that are now in RobotState are set by its _start_query method. But I think some of these variables are probably not correctly tracking the actual state of the robot. Ideally this information would come from the SDK in some way but I'm not sure that's possible.

It also sends the stand command repeatedly if no command is running. I'm not sure this is really necessary.