[FEATURE] Add commands for listing and showing sites

This patch adds the following CLI commands:
site:list - shows a list of all configured sites
site:show - shows the configuration of a single site

Resolves: #86066
Releases: master
Change-Id: I9bfecceea7a28f81f99373ea847e868289de0c70
Reviewed-on: https://review.typo3.org/58104


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: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>