dankbar: support multiple bars and per-display bars

- Migrate settings to v2
  - Up to 4 bars
  - Per-bar settings instead of global

quickshell/Modules/Lock/Keyboard.qml

@@ -8,7 +8,7 @@ Rectangle {
     anchors.bottom: parent.bottom
     anchors.left: parent.left
     anchors.right: parent.right
-    color: Theme.widgetBackground
+    color: Theme.surfaceContainerHigh
 
     signal dismissed