[TASK] Acceptance test installing TYPO3 on pgsql

A basic acceptance tests clicking through installer
using a postgres sql db connection, checking backend login
and installing the introduction package.

Change-Id: I7408e8580d84e235a1f91399684a80025a62e0e8
Resolves: #81602
Releases: master, 8.7
Reviewed-on: https://review.typo3.org/53250


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>