QML-UI: Layout improvements in app list and details header

- fix spacing and sizing in TopBar
- use an anchor layout for the delegate and split out labels and values: this
  allows more uniform alignment
- add the subsurface mobile icon to the first page
- various visual touch-ups to taste

Signed-off-by: Sebastian Kügler <sebas@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-mobile/main.qml

@@ -100,11 +100,21 @@ ApplicationWindow {
 						anchors.leftMargin: units.spacing
 						anchors.right: topPart.right
 						anchors.rightMargin: units.spacing
+						Image {
+							source: "qrc:/qml/subsurface-mobile-icon.png"
+							Layout.maximumWidth: units.gridUnit * 2
+							Layout.preferredWidth: units.gridUnit * 2
+							Layout.preferredHeight: units.gridUnit * 2
+						}
 						Text {
 							text: qsTr("Subsurface mobile")
 							font.pointSize: 18
+							Layout.fillWidth: false
 							color: theme.accentTextColor
 						}
+						Item {
+							Layout.fillWidth: true
+						}
 						Button {
 							id: prefsButton
 							text: "\u22ee"