[TASK] Add HTTP headers to Frontend Response object

HTTP Headers are added to the PSR-7 response object now
within TSFE.

They are then sent at the very end of the request process.

A bw compat layer is added as well.

Resolves: #86486
Releases: master
Change-Id: Ifdeaab26868d0cf60dd87d52046a2565c4971488
Reviewed-on: https://review.typo3.org/58499


Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: Benjamin Franzke <bfr@qbus.de>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>