RESTful slider, MQTTSlider

There is Rest Switches and sensors and also MQTTSwitches and sensors but no sliders. It is aat the moment quite complicated to set this up with automations. Would make life much easier if a RESTFul Slider would be existing.

I would love to have a MQTT based slider. I can use it for whatever i need to. (In my case i want a volume control for a sound system). There is no easy way to have a slider connected to MQTT (maybe with automation but i would like auto discovery as well).