Add entities for Fuel upgrade

Adds api_version, fuel_version, openstack_version, repo_metadata, puppet_modules_source, puppet_manifests_source to
messages for orchestrator. Corresponding field is added to 'Cluster' DB table. 'ReleaseOrchestratorData' DB table is added.
Additional fixture '/etc/nailgun/fixtures/repodata.yaml' is expected to be provided by puppet on master node installation.
Additional parameter 'version->api' in 'version.yaml' is expected to be provided by puppet as well.

Implements: blueprint fuel-upgrade

Change-Id: Ic86fb52c99aaee6a75536a153ff61fdd776c73f7