Refactored (unused) unzip processor to use unpack()

Rafactoring of the appearently unused processor unzip. This processor is newly used by the "extract archive" filetree-contextmenu feature proposed here https://github.com/modxcms/revolution/pull/11352

PR #11352 also works without this refactored processor as I corrected the old version too...but this is much more elegant I think.

This PR is dependent on PRs:
https://github.com/modxcms/revolution/pull/11355
https://github.com/modxcms/revolution/pull/11354