[FEATURE] Command to generate Fluid schema files

The XSD schema generator, added with Fluid Standalone 2.12,
is applied to TYPO3's Fluid integration. This provides
autocompletion for supporting IDEs (like PhpStorm) by executing
the CLI command added with this patch.

Resolves: #104114
Releases: main
Change-Id: Id9f996820483e5af21506cdde2221b2be65a38d8
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/84720


Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>