logger: add a dedicated QML logging Singleton

- adds log.info/error/debug/warn/fatal
- adds ability to write logs to any file
- add CLI options in addition to env to set log levels

quickshell/Modals/Common/DankModal.qml

@@ -7,6 +7,7 @@ import qs.Widgets
 
 Item {
     id: root
+    readonly property var log: Log.scoped("DankModal")
 
     property string layerNamespace: "dms:modal"
     property alias content: contentLoader.sourceComponent
@@ -246,10 +247,10 @@ Item {
                 return WlrLayershell.Overlay;
             switch (Quickshell.env("DMS_MODAL_LAYER")) {
             case "bottom":
-                console.error("DankModal: 'bottom' layer is not valid for modals. Defaulting to 'top' layer.");
+                log.error("'bottom' layer is not valid for modals. Defaulting to 'top' layer.");
                 return WlrLayershell.Top;
             case "background":
-                console.error("DankModal: 'background' layer is not valid for modals. Defaulting to 'top' layer.");
+                log.error("'background' layer is not valid for modals. Defaulting to 'top' layer.");
                 return WlrLayershell.Top;
             case "overlay":
                 return WlrLayershell.Overlay;