Introduce openstack-server-release-jobs template

Add a new template for server projects that contains the usual release
steps.

The effective change of the configuration is an added
merge-release-tag for kite which needed an adjustment in projects.yaml
as well.

Change-Id: I5bb41da4310434785f42bbaca1d2607b1b3d7895
Merge "Introduce openstack-server-release-jobs template"