Added switchLevel capability support. Parameter support for Leviton 4 speed controller.

[csstup]

• Added support for switchLevel capability. Previous default "zwave fan switch" DTH supported it, and its needed for better Alexa support. For instance requesting the fan turn on to "25%" instead of having to know the level names. And the speed is only controllable from the Alexa app via switchLevel.
• Added preferences/settings for leviton 4 speed fan.

Tested on Leviton 4 speed fan controller model ZW4SF.

Please let me know if I can add anything else!

[greens]

We made a conscious decision to drop the switchLevel capability as it was duplicating behavior. As you mentioned, it was originally included to make integration with SmartLighting possible, but we're trying to be a bit stricter about our capability mappings these days.

[csstup]

Thanks for looking at my PR, Steven!

SwitchLevel was more for Alexa integration. It would be great if ST->Alexa could tighten up fan control natively with speeds instead of switchlevel.

[greens]

@csstup Definitely agree with you. I'll see if I can bring it up with our voice team.

[CLAassistant]

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