make player add and remove itself from referencer

scripts/player.gd

@@ -28,6 +28,15 @@ func _ready() -> void:
 
 	_respawn_point = global_position
 	_camera.make_current()
+	Referencer.player = self
+	Referencer.main_camera = _camera
+
+
+func _exit_tree() -> void:
+	if not is_multiplayer_authority():
+		return
+	Referencer.player = null
+	Referencer.main_camera = null
 
 
 func _process(delta: float) -> void: