Add UUID config to simulator visual sensors (facebookresearch#472)

* Add UUID config to simulator visual sensors

* Add comments about UUID and add to BumpSensor

* Incorporate suggestions

* Remove unused code

* Make base sensor have overidable UUID

habitat/core/simulator.py

@@ -63,7 +63,11 @@ class Sensor:
 
     def __init__(self, *args: Any, **kwargs: Any) -> None:
         self.config = kwargs["config"] if "config" in kwargs else None
-        self.uuid = self._get_uuid(*args, **kwargs)
+        if hasattr(self.config, "UUID"):
+            # We allow any sensor config to override the UUID
+            self.uuid = self.config.UUID
+        else:
+            self.uuid = self._get_uuid(*args, **kwargs)
         self.sensor_type = self._get_sensor_type(*args, **kwargs)
         self.observation_space = self._get_observation_space(*args, **kwargs)