Device - gNMI OpenConfig Driver:

- Added TODO.txt

src/device/service/drivers/gnmi_openconfig/TODO.txt

+- create L3-VPN per tenant
+- update README.md
+- update    parse()   @ InterfaceCounter.py
+- update    compose() @ NetworkInstance.py
+- update    compose() @ NetworkInstanceInterface.py
+- implement parse()   @ NetworkInstanceInterface.py
+- update    compose() @ NetworkInstanceStaticRoute.py
+- implement parse()   @ NetworkInstanceStaticRoute.py
+- Fix MonitoringThread.py
+
+
+there is an error removing static routes that makes unitary tests to crash
+uncomment commented check_config_network_instance and validate
+
+- implement L2 VPN with BGP
+- implement L3 VPN with BGP
+- test static routes with ping
+
+
+- test delete service
+
+homogeneize attribute names
+/network_instance[teraflowsdn]/interface[Ethernet1.0]	
+  id: Ethernet1.0
+  if_name: Ethernet1      <<< 1
+  interface: Ethernet1    <<< 1
+  name: teraflowsdn
+  sif_index: 0            <<< 2
+  subinterface: 0         <<< 2
+
+- update README.md