Foreman-packaging PR tests

I set up PR tests on foreman-packaging today for the rpm/develop branch,
but you should take them with a pinch of salt for now and double check
the right packages built.

The aim is to have it test whether a package directory, when changed,
will still build as a scratch. Currently that's not reliable as it's
hard to see whether the package is a plugin or not, and which tito
releaser to use. I'll try and make this more reliable soon.

Most currently open PRs are "failed" as a bug in my test script caused
the wrong packages to be built, so I cancelled them. If you want, you
can always [test] again.

ยทยทยท -- Dominic Cleal Red Hat Engineering