[FEATURE] Categories-based tt_content menu

Provide a new menu/sitemap type for displaying list
of categorized content elements. The default rendering
simply provides links to the parent page with
anchor pointing to the specific content element.
Refactor the RECORDS object.

Resolves: #52137
Documentation: #52920
Releases: 6.2
Change-Id: I59c9eeb63148eaf12d8810fd7e64628e3f2d61aa
Reviewed-on: https://review.typo3.org/23905
Reviewed-by: Markus Klein
Tested-by: Markus Klein