[TASK] Add loading indicator to "Manage Reference Index"

Processing of "Manage Reference Index" actions
(check/update) can take quite some time.

To give the user better feedback of the current state
a loading indicator has been added and buttons
are disabled during processing.

Resolves: #95094
Releases: master
Change-Id: Ia1d19eb6d63c4d980e548820cc795b5c0b892164
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70879


Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Jochen <rothjochen@gmail.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>