Uses PSR-7 instead of plain echo() and die - and shutdown the
install tool properly (except for redirects currently).

In the future, we should introduce proper PSR-7 response objects
for certain responses (JSON, Redirect) but this will happen in
a separate step.

Resolves: #82268
Releases: master
Change-Id: If8124f975936f6205f45009d30d979204765d8d1
Reviewed-on: https://review.typo3.org/53856


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>