Prevent screen turning off during playback

Closes: #157

XDG portals expose a D-Bus interface allowing apps to prevent screen
idling, user switching, and other actions. That interface,
org.freedesktop.portal.Inhibit, does all of the heavy lifting here.

Idling = the screen dimming or shutting off.

Idling is inhibited when a video is actively playing.
Idling is NOT inhibited when videos aren't playing - this includes
paused or stopped videos.

src/config.rs

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 
 use cosmic::{
-    cosmic_config::{self, cosmic_config_derive::CosmicConfigEntry, CosmicConfigEntry},
+    cosmic_config::{self, CosmicConfigEntry, cosmic_config_derive::CosmicConfigEntry},
     theme,
 };
 use serde::{Deserialize, Serialize};