Added stub QML page for discovery action

CURA-336

DiscoverUM3Action.py

@@ -3,6 +3,7 @@ from cura.MachineAction import MachineAction
 class DiscoverUM3Action(MachineAction):
     def __init__(self):
         super().__init__("DiscoverUM3Action", "Discover printers")
+        self._qml_url = "DiscoverUM3Action.qml"
 
     def _execute(self):
         pass

DiscoverUM3Action.qml

@@ -0,0 +1,26 @@
+import UM 1.2 as UM
+import Cura 1.0 as Cura
+
+import QtQuick 2.2
+import QtQuick.Controls 1.1
+import QtQuick.Layouts 1.1
+import QtQuick.Window 2.1
+
+Cura.MachineAction
+{
+    anchors.fill: parent;
+    Item
+    {
+        anchors.fill: parent;
+        id: discoverUM3Action
+        UM.I18nCatalog { id: catalog; name:"cura"}
+        Label
+        {
+            id: pageTitle
+            width: parent.width
+            text: catalog.i18nc("@title", "Discover Printer")
+            wrapMode: Text.WordWrap
+            font.pointSize: 18;
+        }
+    }
+}