[!!!][TASK] Make Extbase handle PSR-7 responses only

With this patch, Extbase does no longer handle/return
extbase responses whose api was defined by the extbase
ResponseInterfacer. Instead, Extbase does create a PSR-7
compatible response object and passes it back through
the request handling stack.

Since PSR-7 requires response objects to be immutable,
the response object is no longer accessible as property
of class ActionController. It is also no longer accessible
through the ControllerContext class. In fact, the response
is completely hidden from the user and can no longer be
changed.

To address this issue, an upcoming patch will enable users
to return user controlled responses from within controller
actions instead of just returning content strings. User will
then be forced to return response objects with the content
and all necessary headers, such as the content-type, set.

Since the Response class has been deleted, it is no longer
usable in user land code. It should be replaced with PSR-7
compatible response objects to stay compatible with response
handlers of both the core and extbase.

Releases: master
Resolves: #92502
Change-Id: I4d5dc1478be6dd25b43f6249139eeb4ce5cc3094
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66070


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>