Godot OpenXR Vendors plugin v3.0.0 beta 3

Important: This is the third beta release of the 3.0.0 version of the Godot OpenXR Vendors plugin. This version of the plugin is designed to work with the upcoming Godot 4.3 release.

Note: Part of the passthrough logic in Godot has moved into the vendor plugin and you will need to update to this version for working passthrough.

Changes in this release since beta 2

• Documentation & API docs updates
• Statically link with libgcc and libstdc++ for more Linux compatibility
• Update godot-cpp to Godot 4.3-beta2
• Update Godot Android library dependency to 4.3.beta
• Add sample projects:
  • Add fb_hand_tracking sample
  • Add fb-scene-sample sample
• Use build_profile to improve build times
• Add export presets for all supported platforms
• Use Khronos loader for Pico and add store required manifest entries

Full Changelog: 3.0.0-beta2...3.0.0-beta3