Gamepad unique id

## What problem does this solve or what need does it fill?

I need to remember which controller was which between process stops/starts.

## What solution would you like?

gilrs provides multiple identifiers, like "os name" and "uuid". Bevy prints out an id like `/dev/input/event13` at startup which would be unique to the system and consistent, I assume that's the os name. Exposing one or both of those would solve this.

## What alternative(s) have you considered?

The gamepad currently is an integer which changes per session.

The name is generic: I have 2 xbox360-like controllers plugged in and the names of both are "Xbox 360 Controller" so it's not possible to differentiate them.

## Additional context

Do typical amazon-sourced controllers have legit usb or info, maybe some are cloned and would have the same uuid? I'm not sure. UUID could be useful for per-controller calibration settings etc, where the os id might be useful for "whatever controller is plugged into the same port", maybe if someone needs to swap controllers mid-game. Both would work in my case, however.