Add dynamic matrix axis which populates with all connected UDIDs at build time

We have various jobs with a matrix axis containing a list of hardcoded UDIDs.

This is ugly, and fragile, if somebody ever happens to unplug a device from the Jenkins cluster.

So... this adds a dynamic matrix axis which, at build time, gathers all the *currently-available* UDIDs.

I upped the POM requirement to 1.480, as the dynamic matrix stuff was added around ~1.471 but I believe had some bugs in the following few versions, and 1.480 is an LTS version.