Add setting for server sent commands per frame limit

Use higher of this and existing commands per frame limit setting
for server-originating commands, e.g. GS

src/table/settings/network_settings.ini

@@ -69,6 +69,15 @@ min      = 1
 max      = 65535
 cat      = SC_EXPERT
 
+[SDTC_VAR]
+var      = network.commands_per_frame_server
+type     = SLE_UINT16
+flags    = SF_NOT_IN_SAVE | SF_NO_NETWORK_SYNC | SF_NETWORK_ONLY
+def      = 16
+min      = 1
+max      = 65535
+cat      = SC_EXPERT
+
 [SDTC_VAR]
 var      = network.max_commands_in_queue
 type     = SLE_UINT16