Tooltip panel component#263

There are cases where a tooltip component would come in quite handy in the panel, especially with certain custom blocks.

IMO, that’s something that’s better off in a plugin than the core.

If I’m not mistaken, there’s already handling in the core for tooltips (some native Kirby elements have them, I believe), so implementing this is more about abstracting it into a reusable component that we can utilize than it is about adding anything new to the core.