updated types, states, etc. according to naming conventions, WIP

api/apiIntegration_test.go

api/api_test.go

api/grpc.go

api/initialise_test.go

api/pnd.go

api/pnd_test.go

go.mod

go.sum

interfaces/change/change.go

northbound/server/core.go

northbound/server/pnd_test.go

nucleus/change.go

nucleus/change_test.go

nucleus/device.go

nucleus/gnmi_transport.go

nucleus/gnmi_transport_test.go

nucleus/principalNetworkDomain.go

nucleus/principalNetworkDomain_test.go

nucleus/southbound.go

nucleus/southbound_test.go