quickshell: drop support for 0.2, require 0.3+

- Remove all compat code
- Rewire LegacyNetworkService to use Quickshell.Networking
- Add parentWindow to settings child windows

quickshell/Modules/Lock/VideoScreensaverPlayer.qml

@@ -0,0 +1,8 @@
+import QtQuick
+import QtMultimedia
+
+Video {
+    fillMode: VideoOutput.PreserveAspectCrop
+    loops: MediaPlayer.Infinite
+    volume: 0
+}