Add service NodePort information in server description

Add service NodePort information in server description

Kubernetes context provides a list of NodePort services to each
replication controller. "_get_server" should return this information
in the server description dictionary:

  server: { ...
    'service_ports': <list of NodePort objects>
  }

Relevant NodePort object attributes:
  - port
  - node_port
  - target_port
  - protocol
  - name

JIRA: YARDSTICK-1313

Change-Id: Ie481cdea4761f162e3b3329e4e2c5a982faea9e9
Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>