FR: Auto color filter "(muted)"

[Phazmaonline]

I would like to be able to automatically color muted items white, without also having white tracks in the arranger.

Obviously I would first need Item as a rule type for this, but there exists already a FR for it which I supported.

So with this FR I specifically request to add "muted" as a filter to tracks and items for applying coloring.

This would also be useful independent of the combination with items. For example the track layout could change for muted tracks, removing controls which shouldn't be changed while a track is muted.