feat(sbb-tooltip): initial implementation

[kyubisation]

This PR implements the tooltip.

To discuss and decide:

• [x] Is the attribute approach acceptable?
  • [ ] ~~Should sbb-tooltip (problems with linter and IDEs) or data-sbb-tooltip be used?~~
• [x] Is the overlay controller an acceptable solution for overlays?
• [ ] ~~Should we start using native CSS Anchor Positioning, as it is now partially supported in Chromium based browsers?~~ Wait for improved browser support.
• [x] UX: Should the tooltip always be below/above or can it be before/after (as currently implemented)?

Still to do:

• [ ] Documentation
• [ ] Tests