[kcms/keyboard] tastenbrett: right-align l3 and l4

After feedback from Harald Sitter, right align the bottom right and top
right components of the key cap, which contain the level3 and level4
symbols (typically accessed by AltGr and AltGr+Shift).

kcms/keyboard/tastenbrett/qml/KeyCap.qml

@@ -40,7 +40,7 @@ Item {
     KeyCapLabel {
         id: topRight
         width: parent.width /2.0
-        horizontalAlignment: Text.AlignLeft
+        horizontalAlignment: Text.AlignRight
         height: parent.height  /2.0
         anchors.top: parent.top
         anchors.right: parent.right
@@ -58,7 +58,7 @@ Item {
     KeyCapLabel {
         id: bottomRight
         width: parent.width /2.0
-        horizontalAlignment: Text.AlignLeft
+        horizontalAlignment: Text.AlignRight
         height: parent.height  /2.0
         anchors.bottom: parent.bottom
         anchors.right: parent.right