feat: make CLI::input() testable

[kenjis]

Description
Fixes #6076

• add PhpStreamWrapper
• modify CLI::input() for testing

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[MGatner]

I'm not very familiar with PHP stream registration. I think @paulbalandan has done a lot of our work in this area and might be able to review. The test use looks good and run was successful so I assume this is working as intended. 💪

[paulbalandan]

I only have two occasions where I encountered stream wrappers (infection/include-interceptor and dg/bypass-finals) which I think won't mess with this php wrapper since both are wrappers for the file protocol.

I just have a few comments.

[paulbalandan]

Last thing, should this class also have a public $context property?

[kenjis]

should this class also have a public $context property?

PHP manual says:

This property must be public so PHP can populate it with the actual context resource.
https://www.php.net/manual/en/class.streamwrapper.php#streamwrapper.props.context

So I'm not sure we really need it, but I added it.

[kenjis]

Added docs.

[MGatner]

Thanks you two, good stuff!