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/show.rs

@@ -76,7 +76,7 @@ impl ListItem for Show {
         false
     }
 
-    fn display_left(&self) -> String {
+    fn display_left(&self, _library: Arc<Library>) -> String {
         format!("{}", self)
     }