added PageSettings and PageSettingsServersList.

- replaced PageLoader with PageType with stackView property.
- added error handling when installing a server/container

client/ui/qml/main2.qml

@@ -27,9 +27,9 @@ Window  {
         color: "#0E0E11"
     }
 
-    PageLoader {
-        id: pageLoader
+    StackView {
         anchors.fill: parent
         focus: true
+        initialItem: PageController.getInitialPage()
     }
 }