Added service plan tab 

Added service plan tab with following features:
1) The tab must consist of a main table and a details table
2) There should be a span across the service columns and a span across the service plan columns. See service instances table for an example
3) There should be a count of instances for this service plan with a detail link/filter to service instances. The link must appear only on the details table.
4) There must be an action (button) with label "Public" and another action with label "Private"
5) There must be a link added to the Service Instances tab which takes user back to the Service Plans tab.
6) There must selenium-based test cases for the new Service Plans tab