Extract Live Data to make it reusable outside XWiki

Live Data is currently a component that is only used inside XWiki.
Since it is an advanced UI element with a complex logic, it is interesting to make it reusable outside XWiki (e.g., in Cristal).

See https://forum.xwiki.org/t/extract-live-data-to-make-it-reusable-outside-xwiki/18103