nixguix: Improve is_tarball detection pattern

This actually includes all query param values as paths to check. When paths have
extensions, it then pattern matches against tarballs if any. When no extension is
detected, it's doing as before, fallbacks to head query the url to have more information
on the file.

Prior to this commit, this only looked over a hard-coded list of values (for hard-coded
keys: file, f, name, url) detected through docker runs. This way of doing it should
decrease future misdetections (when new unknown "keys" show up in the wild).

Related to T3781