This MR adds adds khr/simple_controller emulation for our hand-tracking on Index, so that hopefully people can use it with various traditional controller apps. Some thoughts:
- This adds nothing to the prober or config parsing code - there's currently no way to add controller emulation to "any" driver - and it only works on Index. In the future we might want to do this, or at least come up with another hack to make it work with North Star as well.
- This only emulates select click - bound to pinch. Menu click is possible, of course, but our hand-tracking isn't very good yet, so trying to detect more complicated gestures feels like too much for now.
- Maybe we should implement XR_MSFT_hand_interaction now?
- I couldn't find a name for the driver that I really liked - feel free to suggest something else and/or change it later.