refactor: pass globally mutable config reference

Before, copies of the configuration were passed over. This change also
causes configuration reloads to affect the entire application and is
easier to maintain but introduces some RwLock overhead.

src/track.rs

@@ -154,7 +154,7 @@ impl ListItem for Track {
     }
 
     fn display_center(&self, library: Arc<Library>) -> String {
-        if library.config().album_column.unwrap_or(true) {
+        if library.cfg.values().album_column.unwrap_or(true) {
             self.album.to_string()
         } else {
             "".to_string()
@@ -163,7 +163,7 @@ impl ListItem for Track {
 
     fn display_right(&self, library: Arc<Library>) -> String {
         let saved = if library.is_saved_track(&Playable::Track(self.clone())) {
-            if library.use_nerdfont {
+            if library.cfg.values().use_nerdfont.unwrap_or(false) {
                 "\u{f62b} "
             } else {
                 "✓ "