[TASK] Have minor Page TSconfig module improvements

* Submodule drop-down is shown on page 0 as well since
  page TSconfig is typically available on page 0 as
  well
* Rename route pagetsconfig_records to pagetsconfig_pages
* Headline improvements for page 0

Change-Id: I01eb793124042c34ad4aa21b6dceb058d1f3d9d8
Resolves: #100310
Releases: main
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78265


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Jasmina Ließmann <minapokhalo+typo3@gmail.com>
Reviewed-by: Jasmina Ließmann <minapokhalo+typo3@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>