Position presets on cover tile

Today a cover tile offers open/close/stop and, depending on the entity, a position slider. For blinds and shutters I almost always want a few ixed positions (e.g. 0%, 30%, 70%, 100%, or "shade" / "privacy" / "night"), and dragging a slider on a small touch screen is imprecise and slow.

Proposal: let a cover tile define a list of presets, each with a label, an optional icon, a position (and a tilt, if the entity supports it). Tapping one calls cover.set_cover_position (and set_cover_tilt_position).

Why: one tap instead of a slider drag, and the result is repeatable. It also works better on small tiles, where a slider is hard to use.

Nice to have: highlight the active preset when the current position matches it.