finish renaming and move HandBoneEntities to bevy_mod_xr

Signed-off-by: Schmarni <marnistromer@gmail.com>

crates/bevy_xr/src/hands.rs

@@ -1,8 +1,9 @@
 use bevy::{
-    ecs::component::Component,
+    ecs::{component::Component, entity::Entity},
     math::bool,
     prelude::{Deref, DerefMut},
 };
+pub const HAND_JOINT_COUNT: usize = 26;
 
 #[derive(Clone, Copy, Component, Debug)]
 pub struct LeftHand;
@@ -10,6 +11,9 @@ pub struct LeftHand;
 #[derive(Clone, Copy, Component, Debug)]
 pub struct RightHand;
 
+#[derive(Deref, DerefMut, Component, Clone, Copy)]
+pub struct XrHandBoneEntities(pub [Entity; HAND_JOINT_COUNT]);
+
 #[repr(transparent)]
 #[derive(Clone, Copy, Component, Debug, DerefMut, Deref)]
 pub struct HandBoneRadius(pub f32);