Warn secondary arch folks about change involving: ExclusiveArch or ExcludesArch

[Pierre-Yves Chibon]

Good Morning,

Rel-eng has been wanting a got hook that would notify the people involved with
secondary arches about changes made to packages involving ExclusiveArch or
ExcludesArch.

I took a stab at this hook today and I would like to offer the result for
review.

So with this email is an ansible patch adding the hook and installing it in our
repos.

Things that needs to be tweaked:
- Where to send the email?
- Turn off debug after we confirmed it works
- Currently I install the script as a file not a template, so the URL to point
  to commits in CGIT will be the same in prod and in stg.

Comments and thoughts more than welcome :)

Pierre