New workflow: ZIP archives on input

This pull request:
 * Introduces a new capability for handling ZIP archives on input, in the same spirit as the ZIP output sandboxing.
 * Optimizes the archiving done in LaTeXML::Post::Pack, in order to only deflate textual files and simply store binaries and others.

The status of the code is experimental, I have only performed early experiments successfully. There is certainly need for improving code quality and providing test cases (and possibly an extension to the test framework).

This feature set is central to the CorTeX-based reimplementation of the arXMLiv build system.