cmdmon: save NTS cookies and server keys on dump command

Extend the dump command to save also the server NTS keys and client NTS
cookies. Remove the warning for unset dumpdir.

stubs.c

@@ -331,6 +331,11 @@ NSR_GetActivityReport(RPT_ActivityReport *report)
   memset(report, 0, sizeof (*report));
 }
 
+void
+NSR_DumpAuthData(void)
+{
+}
+
 #ifndef FEAT_CMDMON
 
 void
@@ -515,6 +520,11 @@ NNC_ChangeAddress(NNC_Instance inst, IPAddr *address)
 {
 }
 
+void
+NNC_DumpData(NNC_Instance inst)
+{
+}
+
 void
 NKC_Initialise(void)
 {
@@ -535,4 +545,9 @@ NKS_Finalise(void)
 {
 }
 
+void
+NKS_DumpKeys(void)
+{
+}
+
 #endif /* !FEAT_NTS */