Add a behavior tree to the enemy

Add the Beehave addon.
Make the enemy do the same thing as before but with a behavior tree.

addons/beehave/utils/utils.gd

@@ -0,0 +1,22 @@
+@tool
+class_name BeehaveUtils
+
+
+static func get_plugin() -> EditorPlugin:
+	var tree: SceneTree = Engine.get_main_loop()
+	return tree.get_root().get_child(0).get_node_or_null("BeehavePlugin")
+
+
+static func get_editor_scale() -> float:
+	var plugin := get_plugin()
+	if plugin:
+		return plugin.get_editor_interface().get_editor_scale()
+	return 1.0
+
+
+static func get_frames() -> RefCounted:
+	var plugin := get_plugin()
+	if plugin:
+		return plugin.frames
+	push_error("Can't find Beehave Plugin")
+	return null