Adds support for mouse pointer hovering to trigger tooltips, as well as custom timeouts for the tooltip durations, and a custom decoration. It also makes the tooltip be fully opaque when shown, and fade in over 150ms, and fade out over 75ms, and draw a 4.0 corner radius, all to conform with the material spec. Prior to this change, it was using a corner radius of 2.0 when shown, and faded in and out over 200ms.

Fixes #22817