network: better default settings for cellular connections (#330)

* network/mobile: remove serial config

This is based on assumptions and is unnecessary for most modems.
For almost a decade, the NM applet has not done this, see:

https://gitlab.gnome.org/GNOME/network-manager-applet/-/commit/604d7db2ca49a44fb095c787793ba3afcb50fdd9

* network/mobile: allow dual stack cellular connections

Copied from:
https://gitlab.gnome.org/GNOME/network-manager-applet/-/commit/6701ae6fece2ec8f8597ea837d890fdbfe82aadc

panels/network/network-dialogs.c

@@ -337,14 +337,13 @@ cdma_mobile_wizard_done (NMAMobileWizard *wizard,
 		              NULL);
 		nm_connection_add_setting (connection, setting);
 
-		/* Serial setting */
-		setting = nm_setting_serial_new ();
-		g_object_set (setting,
-		              NM_SETTING_SERIAL_BAUD, 115200,
-		              NM_SETTING_SERIAL_BITS, 8,
-		              NM_SETTING_SERIAL_PARITY, 'n',
-		              NM_SETTING_SERIAL_STOPBITS, 1,
-		              NULL);
+		/* Default to IPv4 & IPv6 'automatic' addressing */
+		setting = nm_setting_ip4_config_new ();
+		g_object_set (setting, NM_SETTING_IP_CONFIG_METHOD, NM_SETTING_IP4_CONFIG_METHOD_AUTO, NULL);
+		nm_connection_add_setting (connection, setting);
+
+		setting = nm_setting_ip6_config_new ();
+		g_object_set (setting, NM_SETTING_IP_CONFIG_METHOD, NM_SETTING_IP6_CONFIG_METHOD_AUTO, NULL);
 		nm_connection_add_setting (connection, setting);
 
 		nm_connection_add_setting (connection, nm_setting_ppp_new ());
@@ -400,14 +399,13 @@ gsm_mobile_wizard_done (NMAMobileWizard *wizard,
 		              NULL);
 		nm_connection_add_setting (connection, setting);
 
-		/* Serial setting */
-		setting = nm_setting_serial_new ();
-		g_object_set (setting,
-		              NM_SETTING_SERIAL_BAUD, 115200,
-		              NM_SETTING_SERIAL_BITS, 8,
-		              NM_SETTING_SERIAL_PARITY, 'n',
-		              NM_SETTING_SERIAL_STOPBITS, 1,
-		              NULL);
+		/* Default to IPv4 & IPv6 'automatic' addressing */
+		setting = nm_setting_ip4_config_new ();
+		g_object_set (setting, NM_SETTING_IP_CONFIG_METHOD, NM_SETTING_IP4_CONFIG_METHOD_AUTO, NULL);
+		nm_connection_add_setting (connection, setting);
+
+		setting = nm_setting_ip6_config_new ();
+		g_object_set (setting, NM_SETTING_IP_CONFIG_METHOD, NM_SETTING_IP6_CONFIG_METHOD_AUTO, NULL);
 		nm_connection_add_setting (connection, setting);
 
 		nm_connection_add_setting (connection, nm_setting_ppp_new ());