Draft: d/xreal_light: Basic Xreal Light driver

CC #328, webpage!47

I'm opening this MR early so that:

1. Contributors can point me in the right direction; and
2. Whatever code I have is available to build off of if I abandon this effort

To Do

• Get monado/utilities/xr-hardware!31 (merged) merged (blocker)
• Get !2156 merged (dependency)
• Wait on !2150 (merged) to be merged (merge conflicts)
• CMakeLists.txt
  • Add XRT_BUILD_DRIVER_XREAL_LIGHT option_with_deps (dependent on hidapi)
  • Add "XREAL_LIGHT" to AVAILABLE_DRIVERS list
  • Add debug message
• Create src/xrt/targets/common/target_builder_xreal_light.c
  • Add target to target_lists.c
  • Add target target_builder_interface.h
  • Add target to CMakeLists.txt
  • t_builder_xreal_light_create
    • estimate_system
      • Check for OV580
      • Check for MCU
      • Check for display matching EDID data
    • open_system
      • Get xrt_prober_device for OV580
      • Get xrt_prober_device for MCU
      • Open interfaces as needed
      • Pass interfaces to xreal_light_hmd_create
• xreal_light_hmd_create
  • Figure out which inputs to create
    • XRT_INPUT_GENERIC_HEAD_POSE -> 3DoF (Does this also do 6DoF or not?)
    • XRT_INPUT_GENERIC_STAGE_SPACE_POSE? -> Is this for 6DoF?
    • XRT_INPUT_GENERIC_HAND_TRACKING_RIGHT & XRT_INPUT_GENERIC_HAND_TRACKING_LEFT? -> Or is this done in a separate driver
  • Figure out which outputs to create
    • None?
  • xreal_light_hmd_get_tracked_pose
  • xreal_light_hmd_destroy
  • xreal_light_hmd_update_inputs
  • IMU reading thread
  • Hand tracking
  • 6DoF tracking
  • Figure out what else needs to be implemented to get a working driver
• Finish this TODO list

References

https://voidcomputing.hu/blog/good-bad-ugly/

https://github.com/badicsalex/ar-drivers-rs/blob/master/src/nreal_light.rs

!1798 (merged)

!1930 (merged)

https://pastebin.com/wcmstRN8