feat: introduce .env.example, docs

The example includes options that are expected to be changed. It also includes a reference to where in the docs you can find a full list of options.

ref: N25B-352

src/control_backend/agents/actuation/robot_speech_agent.py

@@ -29,7 +29,7 @@ class RobotSpeechAgent(BaseAgent):
     def __init__(
         self,
         name: str,
-        address=settings.zmq_settings.ri_command_address,
+        address: str,
         bind=False,
     ):
         super().__init__(name)