This change adds more links for Packagist to all TYPO3 System Extensions.

This is especially relevant for Packagist to point to the main
repository and provide all information for the subtree split packages.

The support section now includes the following information:

* chat: a link to "https://typo3.org/help" where finally also the link to
  Slack can be found
* docs: a link to the Official Docs "https://docs.typo3.org"
* issues: a link to the issue tracker at "https://forge.typo3.org"
* source: a link to the TYPO3 main repository on Github
  "https://github.com/TYPO3/TYPO3.CMS"

Unused support options for packagist.org in `typo3/cms` are removed.

Resolves: #90622
Releases: master
Change-Id: I08b4ec80cd2d06b70ea40439bcc33c08d3eb5f03
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63534


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Björn Jacob <bjoern.jacob@tritum.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Benni Mack <benni@typo3.org>