Update ARKit for Godot 4.3

[celyk]

Continues #64

So far I tried to do the minimum amount of work to get this working in Godot 4.x. We should consider porting it to a GDExtension as mux213 suggested

arkit-3-low.mp4

Demo project
https://github.com/celyk/godot_xr_test_projects/tree/master/ARKit

What's working

• Basic AR
• Screen orientations (provided feed_transform is used to adjust the camera feed)
• Anchor positions
• Anchor plane mesh
• ARKit hitTest for touching anchors

What's not working

• With background_camera_feed_id set color and orientation are wrong
• Standard Godot ray intersect (Wrong camera FOV?)

[RubenGarcia]

I´m also interested in this being merged.

[Makosai]

I merged this into #64. If you do any extra work, I'll merge it over there and I'll try to coordinate with people to get this released. Great work!