Integrate os-nosdn-osm scenario

Integrate os-nosdn-osm scenario

This change integrates os-nosdn-osm scenario.

The installation of OSM is done as post-deployment. This is achieved by
the addition of the new playbook named post-deployment.yml in scenario
role folder.

This mechanism is available for all OpenStack scenarios. If anything
needs to be done for a specific scenario as part of the post-deployment,
it can be achieved by creating playbook post-deployment.yml.

If post-deployment.yml exists in scenario role, the framework will run
it once the regular deployment playbooks are run successfully. If the
file does not exist, it will be skipped.

The location of the post-deployment.yml is
    releng-xci-scenarios/<scenario>/role/<scenario>/tasks/post-deployment.yml

This is only implemented for OpenStack scenarios currently and similar
mechanism is needed for K8S scenarios as well which will be implemented
in a separate change.

installer-type:osa
deploy-scenario:os-nosdn-osm

Change-Id: I16780abffca39699eb2f38f662479f0e4d551504
Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>