Feature: #86051 - Show extensions via CLI 

See forge#86051

Description 

A new command extension:list is added, which can be executed via Command Line typo3/sysext/core/bin/typo3 extension:list.

This command shows all currently installed (= active) extensions. The option --all also includes all inactive extensions. If the list of inactive extensions should be shown, the command --inactive will show only the extensions available for installation.

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

Impact 

In order to show which extensions can be uninstalled or installed via CLI, the new command is a good companion for the existing commands extension:activate and extension:deactivate.