- use types on the DHCP API so that the same data is sent in comfing messages and in dumps
- add the DHCP client dump API
- update VOM to refelct API changes
- rename VOM class dhcp_config* dhcp_client*
- the VOM dhcp_client class maintains the lease data (which it reads on a dump) for clients to read
Change-Id: I2a43463937cbd80c01d45798e74b21288d8b8ead
Signed-off-by: Neale Ranns <neale.ranns@cisco.com>