Add job to check projects.yaml alphabetized

It checks that projects.yaml alphabetized and prints list of projects
that should be sorted. Additionally, it adds new job as non-voting to
the openstack-infra/config project.

Change-Id: I9c0eb5072a5b1446ee654296e60c1f8587a3a7ad
Merge "Add job to check projects.yaml alphabetized"