Added tab navigation functional. (#721)

- Added tab navigation functional.
- In basic types added parentFlickable property, which will help to ensure, that the item is visible within flickable parent during tab navigation.
- Added focus state for some basic types.
- In PageType qml file added lastItemTabClicked function, which will help to focus tab bar buttons when the last tab on the current page clicked.
- Added Focus for back button for all pages and drawers.
- Added scroll on tab for Servers ListView on PageHome.

client/ui/controllers/pageController.h

@@ -123,6 +123,9 @@ signals:
     void escapePressed();
     void closeTopDrawer();
 
+    void forceTabBarActiveFocus();
+    void forceStackActiveFocus();
+
 private:
     QSharedPointer<ServersModel> m_serversModel;