With the move towards autodetecting available features, there is no reason to keep SmartPlug around.
kasa.smart.SmartPlug is removed in favor of kasa.smart.SmartDevice which offers the same functionality.
Information about auto_off can be accessed using Features of the AutoOffModule on supported devices.
Co-authored-by: Steven B. <51370195+sdb9696@users.noreply.github.com>
This adds a generic interface for all device classes to introspect available device features,
that is necessary to make it easier to support a wide variety of supported devices with different set of features.
This will allow constructing generic interfaces (e.g., in homeassistant) that fetch and change these features without hard-coding the API calls.
`Device.features()` now returns a mapping of `<identifier, Feature>` where the `Feature` contains all necessary information (like the name, the icon, a way to get and change the setting) to present and change the defined feature through its interface.
