Add new anchorSelect prop to improve how to attach multiple anchors to the same tooltip

[gabrieljablonski]

Turns out there might've been a much much easier way to do multiple anchors than using the provider. anchorSelect should be a CSS selector to find the anchor elements.

The aim of this pull request:

• Allow attaching multiple anchor elements to the same tooltip using simply a CSS selector.
• Maybe deprecate anchorId and point to anchorSelect (keeping both as regular props might be fine as well).
• If the provider/wrapper method doesn't prove to offer anything more than using selectors, we should deprecate it and point users to the anchorSelect prop (it's important to keep the API so code using the provider/wrapper still works).
• Warn in non-production environment if selector doesn't match anything/is invalid. Fail silently in production.
• Evaluate viability for a default selector such as [data-tooltip-for='${tooltipId}']. This way we could have something like v4's data-for attribute.
• Explain on the getting started page very clearly that anchorId and the provider and wrapper have been deprecated.
• Update docs to use mainly anchorSelect and data-tooltip-for, while pointing out very clearly that anchorId has been deprecated.
• Add "Provider/Wrapper (DEPRECATED)" page on the examples section.
• Update the "Upgrade Guide" section to reflect these new changes, which are very relevant for v4 users
• Add "Anchor select" page on the examples section.
• Add link to docs page on @deprecated tags.

Usage might look something like this:

<>
  <span 
    className="react-tooltip-anchor" 
    data-tooltip-content="I am an anchor element!"
  >
    Anchor 1
  </span>
  <span 
    className="react-tooltip-anchor" 
    data-tooltip-content="So am I!"
  >
    Anchor 2
  </span>
  <span 
    className="react-tooltip-anchor" 
    data-tooltip-content="Don't forget about me!"
  >
    Anchor 3
  </span>
  <Tooltip anchorSelect=".react-tooltip-anchor" />
</>

[gabrieljablonski]

The code is slightly messy (but still clean enough) in some places given we shouldn't simply remove the provider and anchorId functionalities. Maybe we could drop it in a future version after some time has passed and most people are already aware of the deprecation warning these changes will trigger.

Now we just have to update the docs. This will take a bit of work since I'd like to change all anchorId to anchorSelect/data-tooltip-for. The "getting started" and the main example pages should have a "warning" style banner indicating anchorId has been deprecated.

[danielbarion]

Also, probably when we remove the anchorId prop, we will need to raise the major version as this is a breaking change.

Nice!

[danielbarion]

Looks good to me 🚀