Overlay anchor

[idoros]

This PR implements the ability to connect an overlay element to a different anchor element in the DOM

• connect an overlay element to an anchor element
  • [x] position overlay relative to anchor on both x and y axis
  • [x] optionally match overlay size to anchor size for both width and height
  • [x] keep position & size on scroll and resize of anchor, overlay or window
• keep in view: handle overlay overflow
  • [x] move into viewport
  • [x] optional overlapAnchor flag for avoiding anchor overlap
• Tooltip
  • [x] props to control position and size

leftovers

• feature: optional shrink size to keep in view