preferences/network: Ungroup VPN and Dialup

* After a bunch of trials, the groupings for VPN and Dial-up
  connections look too busy.  By putting the "connections"
  at the same level as the interfaces things get a bit clearer
  and a little more modern.
* Lots of work to do still for "adding / removing" connections.

src/preferences/network/NetworkWindow.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2004-2015 Haiku Inc. All rights reserved.
+ * Copyright 2004-2019 Haiku Inc., All rights reserved.
  * Distributed under the terms of the MIT License.
  *
  *	Authors:
@@ -449,8 +449,6 @@ NetworkWindow::_ScanAddOns()
 		}
 
 		_SortItemsUnder(fServicesItem);
-		_SortItemsUnder(fDialUpItem);
-		_SortItemsUnder(fVPNItem);
 		_SortItemsUnder(fOtherItem);
 	}
 
@@ -487,16 +485,6 @@ NetworkWindow::_ListItemFor(BNetworkSettingsType type)
 				fServicesItem = _CreateItem(B_TRANSLATE("Services"));
 			return fServicesItem;
 
-		case B_NETWORK_SETTINGS_TYPE_DIAL_UP:
-			if (fDialUpItem == NULL)
-				fDialUpItem = _CreateItem(B_TRANSLATE("Dial Up"));
-			return fDialUpItem;
-
-		case B_NETWORK_SETTINGS_TYPE_VPN:
-			if (fVPNItem == NULL)
-				fVPNItem = _CreateItem(B_TRANSLATE("VPN"));
-			return fVPNItem;
-
 		case B_NETWORK_SETTINGS_TYPE_OTHER:
 			if (fOtherItem == NULL)
 				fOtherItem = _CreateItem(B_TRANSLATE("Other"));