Resolve "Update gRPC abstraction API with missing calls and refactoring"

Description

Complete:

• User
• Role
• Pnd
  • To dicuss: CreatePnd call, uses CreatePndList, should name of the API call be the same even if we only gice the option to add one? Can we make it optional to add multiple in the API call too?
  • Maybe do only one call where a list of one or many is provided?
• Plugin

• Maybe move GetPluginSchemaTree from MNE to Plugin?

• MNE

• For creation: Maybe do only one call where a list of one or many is provided?
• Need to discuss Update function again!

• Auth

Missing for now. Maybe implement?:

• ConfigurationManagement
• Route (Not implemented because this will probably get reworked)
• Topology (Not implemented because this will probably get reworked)
• App

Related to #359

controller/api/managedNetworkElement.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"time"
 
+	"code.fbi.h-da.de/danet/gosdn/api/go/gosdn/conflict"
 	mnepb "code.fbi.h-da.de/danet/gosdn/api/go/gosdn/networkelement"
 	pipb "code.fbi.h-da.de/danet/gosdn/api/go/gosdn/plugin-internal"
 	spb "code.fbi.h-da.de/danet/gosdn/api/go/gosdn/southbound"
@@ -250,3 +251,29 @@ func DeleteNetworkElement(ctx context.Context, addr, pid, mneid string) (*mnepb.
 
 	return client.Delete(ctx, req)
 }
+
+// UpdateNetworkElement changes the metadata of the network element which is stored in the controller storage.
+// Correct resource version needs to be provided to allow a change of the object in the storage.
+func UpdateNetworkElement(ctx context.Context, addr, mneid, updatedName, updatedTransportAddress, updatedPid string, resourceVersion *conflict.Metadata) (*mnepb.UpdateNetworkElementResponse, error) {
+	client, err := nbi.NetworkElementClient(addr, dialOptions...)
+	if err != nil {
+		return nil, err
+	}
+
+	// Note: Consider changing what to update. Some values are quite iffy to change.
+	req := &mnepb.UpdateNetworkElementRequest{
+		Timestamp: time.Now().UnixNano(),
+		NetworkElement: &mnepb.ManagedNetworkElement{
+			Id:               mneid,
+			Name:             updatedName,
+			TransportAddress: updatedTransportAddress,
+			TransportOption: &tpb.TransportOption{
+				Address: updatedTransportAddress,
+			},
+			Metadata:      resourceVersion,
+			AssociatedPnd: updatedPid,
+		},
+	}
+
+	return client.Update(ctx, req)
+}