Update to current upstream and linux-support versions

This MR makes a number of updates which I would have liked to do separately but which turned out to be entangled:

• CI is failing due to the selected linux-support version no longer being available. Cherry-pick changes from firmware-nonfree to update debian/bin/gencontrol.py and the templates to work with current linux-support.

• Those changes depend on the change to use copy-firmware.sh for enumerating firmware files and symlink. So cherry-pick that change as well.

• Cherry-pick all the other relevant changes from firmware-nonfree.

• The copy-firmware.sh script is currently excluded from the orig tarball because its license previously wasn't clear. So update debian/copyright to fix this, and move to a new upstream version. Also add a patch to create WHENCE, which is still excluded from the orig tarball.

• The new upstream version makes copy-firmware.sh call check_whence.py, which is excluded and would always fail due to the added and removed files. Add a patch to revert this.