[TASK] Use core AjaxRequest instead d3.request

d3 is currently manually patched to avoid a
d3.request()/d3.json() bug in chome >= 64 – see #83741.
The patch has not been merged in two years, and d3.request
is deprecated, so it is now replaced.
This will also help to upgrade to D3.js v5/v6 at some
point.

This allows to use an unpatched, vanilla D3.js build again.
While at it, we also streamline the contrib path to avoid the
unecessary d3/ subdirectory.

Commands used:

  grunt build

Resolves: #93186
Related: #83741
Releases: master
Change-Id: I142462272b03edc53c33b2b7233d1902911fc837
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67313


Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Benni Mack <benni@typo3.org>