Moved interfaces to own package

controller.go

initialise_test.go

interfaces/change/change.go

interfaces/device/device.go

interfaces/networkdomain/pnd.go

interfaces/southbound/sbi.go

interfaces/store/store.go

interfaces/transport/transport.go

mocks/Change.go

mocks/ConfigCallback.go

mocks/Device.go

mocks/EscapeFunc.go

mocks/GNMIClient.go

mocks/GNMIServer.go

mocks/GNMI_SubscribeClient.go

mocks/GNMI_SubscribeServer.go

mocks/JSONUnmarshaler.go

mocks/NetworkDomain.go

mocks/PublishFunc.go

mocks/SBIGreeter.go