Implement feature categories (#846)

Initial implementation for feature categories to help downstreams and
our cli tool to categorize the data for more user-friendly manner. As
more and more information is being exposed through the generic features
interface, it is necessary to give some hints to downstreams about how
might want to present the information to users.

This is not a 1:1 mapping to the homeassistant's mental model, and it
will be necessary to fine-tune homeassistant-specific parameters by
other means to polish the presentation.

kasa/device.py

@@ -318,10 +318,10 @@ class Device(ABC):
 
     def _add_feature(self, feature: Feature):
         """Add a new feature to the device."""
-        desc_name = feature.name.lower().replace(" ", "_")
-        if desc_name in self._features:
-            raise KasaException("Duplicate feature name %s" % desc_name)
-        self._features[desc_name] = feature
+        if feature.id in self._features:
+            raise KasaException("Duplicate feature id %s" % feature.id)
+        assert feature.id is not None  # TODO: hack for typing # noqa: S101
+        self._features[feature.id] = feature
 
     @property
     @abstractmethod