Do not depend on the zip tool from Java (any kind of zip file should work)

The ZIP tool used in the integration test of XFF package is creating a ZIP archive with files compressed in a particular order. The XFF input filter depends strongly on this order. Using other ZIP tools to create the XFF package break the input filter.

An idea would be to add an index file in the package, this way, we would not rely on the order of files in the ZIP but on the order of files in the index (and then, any ZIP should be OK).