Creation of the RTree Godot Class

Basic defintions, we are going to see if it fits the use case.

demo/scenes/test.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3 uid="uid://bip0c3ydxx12r"]
+
+[ext_resource type="Script" uid="uid://18smkusl55no" path="res://assets/scripts/test.gd" id="1_errlg"]
+
+[node name="Test" type="Node"]
+script = ExtResource("1_errlg")