Requires fedora-repos-rawhide installed. Tests whether current Fedora
rawhide points to correct release key. Creates also rawhide+1 and
rawhide-1 links to preceding releases. Might be used by
mock-core-configs package directly.

Upcoming rawhide release key and previous release key is often required
by various tools. Prepare symlinks, which can be updated by script on
next Fedora branching.

Obtain rawhide_release from spec file and check our rawhide key points
to matching release.

fedora-eln template uses rawhide+0, rawhide-1 and rawhide-2 keys. Unlike
rawhide +1 and -1. Add additional managed link too.

GitHub worflow already contains similar check. Use similar also for
checking rawhide release here. It should work on any distribution having
git and awk installed, for example ubuntu image.