Import scripts from OS#4862 to have them properly versioned. We use this
to replicate Osmocom related packages from OBS to:
https://download.osmocom.org/obs-mirror
Put it in contrib/, because it doesn't need to get installed to the
jenkins nodes (as it would happen with everything in scripts/).
Related: OS#4862
Change-Id: I3f47cddbcee6c9b85fde77a039dcd5b54dd89f2d
