FEATURE: Introduce --help flag option for existing CLI commands

[crydotsnake]

Upgrade instructions

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Review instructions

This change introduces a new way of using the help function for existing Flow/Neos CLI commands.

Currently you always used:

./flow help user:create

With this change it is possible to use the new --help flag as an alternative at the end of a CLI command:

./flow user:create --help

But of course the first way will also still work!

Demo

https://github.com/neos/flow-development-collection/assets/39345336/4f93f5cf-0435-4344-b37a-0a76b6df7824

Checklist

• [x] Code follows the PSR-2 coding style
• [ ] Tests have been created, run and adjusted as needed
• [ ] The PR is created against the lowest maintained branch
• [ ] Reviewer - PR Title is brief but complete and starts with FEATURE|TASK|BUGFIX
• [ ] Reviewer - The first section explains the change briefly for change-logs
• [ ] Reviewer - Breaking Changes are marked with !!! and have upgrade-instructions