Add support for Stretch (hello-robot) (#409)

Co-authored-by: Remi <remi.cadene@huggingface.co>
Co-authored-by: Remi Cadene <re.cadene@gmail.com>

lerobot/common/robot_devices/robots/utils.py

@@ -9,8 +9,12 @@ def get_arm_id(name, arm_type):
 
 
 class Robot(Protocol):
-    def init_teleop(self): ...
+    # TODO(rcadene, aliberts): Add unit test checking the protocol is implemented in the corresponding classes
+    robot_type: str
+
+    def connect(self): ...
     def run_calibration(self): ...
     def teleop_step(self, record_data=False): ...
     def capture_observation(self): ...
     def send_action(self, action): ...
+    def disconnect(self): ...