Implement port api action

Jobs have done in this patch
1. API to retrieve list of ports: Done
2. API to retrieve details of a single port: Done
3. API to create (insert) a new port: Done
4. API to update an existing port: Done
5. API and RPC to delete an existing port: Done
6. DB API of get_port_list and tests

Change-Id: Idd8c4ab9bc9e1eac2c0c93dfa699c81070f5fbe8
Merge "Implement port api action"