Use devices rather than strings to wait on

You can do a `bps.wait()` on any hashable object as the group. Currently we're only using strings but in some cases it might be more readable and less error prone to use a device e.g. you could use the smargon device when kicking off any moves with the smargon

## Acceptance Criteria
* We replace any groups in the code with devices if it makes sense to do so
* We write some docs about the recommended things to wait on