Slider support for cover

[shotreal]

Simply making you aware of the extension i made, may be it can be of use. If not ignore my pr.
Nice and clear code btw :)

I needed a slider support. (as some others also requested i think)
I included a command topic "set_position_topic" as documented here https://www.home-assistant.io/integrations/cover.mqtt/
the topic is only "activated" for HACover::PositionFeature
I introduced a new callback to get the slider values back.
Borrowed from your HANumber implementation. You might want to check that part.

I have not checked if this value also needs to/ can be feed back to HA, yet (Like you do with the number slider, because i think cover gets that information from the "position_topic") I'm just happy that it works!
I have not written any test cases to verify my code, yet. May be i do.

[erdeidominik99]

Hello!
@shotreal Thank you for the code, it works great, can you help me, how to add the position_open and position_closed parameters? By default the open is 100% and the closed is 0%, but I need the opposite (open 0% close 100%).