feat: audio mixer, Audio app, fix Installer crash

scripts/install_apps.sh

@@ -26,7 +26,7 @@ APPS=(
     "disks|apps/scalable/gparted.svg"
     "devexplorer|apps/scalable/hardware.svg"
     "installer|mimetypes/scalable/text-x-install.svg"
-    "volume|apps/scalable/pavucontrol.svg"
+    "audio|apps/scalable/pavucontrol.svg"
     "music|apps/scalable/audio-player.svg"
     "video|apps/scalable/video-player.svg"
     "bluetooth|apps/scalable/bluetooth.svg"