core/server: add generic dbus service

- Add QML client with subscribe/introspect/getprop/setprop/call
- Add CLI helper `dms notify` that allows async calls with action
  handlers.

quickshell/Widgets/DankActionButton.qml

@@ -13,6 +13,7 @@ StyledRect {
     property bool enabled: true
     property int buttonSize: 32
     property var tooltipText: null
+    property string tooltipSide: "bottom"
 
     signal clicked
     signal entered
@@ -38,5 +39,6 @@ StyledRect {
         onEntered: root.entered()
         onExited: root.exited()
         tooltipText: root.tooltipText
+        tooltipSide: root.tooltipSide
     }
 }