[BUGFIX] Invoke delete command via AJAX

The delete command triggered by the page tree's context menu was invoked
by loading a URL in the module iframe which caused timing issues due to
subsequent requests.

This patch invokes an AJAX call instead to deleted pages.

Resolves: #87416
Releases: master, 9.5
Change-Id: I457df1a21e703f98f6b1a182f6165f60cfd13b21
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60621


Tested-by: Josef Glatz <josefglatz@gmail.com>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Josef Glatz <josefglatz@gmail.com>
Reviewed-by: Richard Haeser <richard@maxserv.com>