[FEATURE] Show extensions via CLI

A new Symfony command "extension:list" allows to list all active
extensions.

Using --all option also includes the currently inactive extensions
available for installation and --inactive only shows the currently
inactive extensions available for installation.

Additional description of the extensions can be shown by --verbose / -v.

Resolves: #86051
Releases: master
Change-Id: I88a370a1c2a0b7a850e2e99afba3a992d4dee661
Reviewed-on: https://review.typo3.org/58094


Reviewed-by: Kevin Appelt <kevin.appelt@icloud.com>
Tested-by: Kevin Appelt <kevin.appelt@icloud.com>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Frans Saris <franssaris@gmail.com>
Tested-by: Frans Saris <franssaris@gmail.com>