Add track_format config option (#800)

* Added track_name_first config option to allow choosing if artists' names should be shown before or after the track name.

* Added active_fields config option, which allows configuration of which columns are visible in Queue/Library view.
This also removes the need for a separate track_name_first and album_column option.

* Fixed README

* Made custom tracklist formatting more flexible.
Updated readme with new instructions.
Reformatted impl member order to match the definitions in traits.rs.

* Added track_name_first config option to allow choosing if artists' names should be shown before or after the track name.

* Added active_fields config option, which allows configuration of which columns are visible in Queue/Library view.
This also removes the need for a separate track_name_first and album_column option.

* Fixed README

* Made custom tracklist formatting more flexible.
Updated readme with new instructions.
Reformatted impl member order to match the definitions in traits.rs.

* Fetch formatting config from library config

Instead of the lazy static mutex

* Moved custom format function to Playable impl as it's a better location to handle both Tracks and Episodes

* Rename from `tracklist_formatting` to `track_format`

Also shorten `format_{left|center|right}` to `{left|center|right}`

Co-authored-by: Henrik Friedrichsen <henrik@affekt.org>

src/model/playlist.rs

@@ -191,11 +191,7 @@ impl ListItem for Playlist {
         }
     }
 
-    fn as_listitem(&self) -> Box<dyn ListItem> {
-        Box::new(self.clone())
-    }
-
-    fn display_left(&self) -> String {
+    fn display_left(&self, _library: Arc<Library>) -> String {
         match self.owner_name.as_ref() {
             Some(owner) => format!("{} • {}", self.name, owner),
             None => self.name.clone(),
@@ -251,14 +247,6 @@ impl ListItem for Playlist {
         }
     }
 
-    fn save(&mut self, library: Arc<Library>) {
-        library.follow_playlist(self);
-    }
-
-    fn unsave(&mut self, library: Arc<Library>) {
-        library.delete_playlist(&self.id);
-    }
-
     fn toggle_saved(&mut self, library: Arc<Library>) {
         // Don't allow users to unsave their own playlists with one keypress
         if !library.is_followed_playlist(self) {
@@ -272,6 +260,14 @@ impl ListItem for Playlist {
         }
     }
 
+    fn save(&mut self, library: Arc<Library>) {
+        library.follow_playlist(self);
+    }
+
+    fn unsave(&mut self, library: Arc<Library>) {
+        library.delete_playlist(&self.id);
+    }
+
     fn open(&self, queue: Arc<Queue>, library: Arc<Library>) -> Option<Box<dyn ViewExt>> {
         Some(PlaylistView::new(queue, library, self).into_boxed_view_ext())
     }
@@ -326,4 +322,8 @@ impl ListItem for Playlist {
             self.owner_id, self.id
         ))
     }
+
+    fn as_listitem(&self) -> Box<dyn ListItem> {
+        Box::new(self.clone())
+    }
 }