Include a header for the settings page for better consistency

Image selected and adapted by Jens

discover/qml/SourcesPage.qml

@@ -74,6 +74,7 @@ DiscoverPage {
 
         headerPositioning: ListView.OverlayHeader
         header: PageHeader {
+            backgroundImage.source: "qrc:/banners/syssettingscrop.jpg"
             extra: RowLayout {
                 anchors {
                     topMargin: Kirigami.Units.smallSpacing

discover/resources.qrc

@@ -40,6 +40,7 @@
     <file>banners/banner.svg</file>
     <file>banners/installedcrop.jpg</file>
     <file>banners/updatescrop.jpg</file>
+    <file>banners/syssettingscrop.jpg</file>
     <file>banners/coffee.jpg</file>
  </qresource>
 </RCC>