Fixed a lot of possible issues raised by a code inspection

app/src/main/java/com/cappielloantonio/play/model/Artist.java

@@ -20,9 +20,7 @@ public class Artist implements Parcelable {
     public static final String DOWNLOADED = "DOWNLOADED";
     public static final String STARRED = "STARRED";
 
-    private List<Genre> genres;
     private List<Album> albums;
-    private List<Song> songs;
     private List<Artist> similarArtists;
 
     private String id;
@@ -222,9 +220,7 @@ public class Artist implements Parcelable {
     }
 
     protected Artist(Parcel in) {
-        this.genres = new ArrayList<>();
         this.albums = new ArrayList<>();
-        this.songs = new ArrayList<>();
         this.id = in.readString();
         this.name = in.readString();
         this.primary = in.readString();

app/src/main/java/com/cappielloantonio/play/model/Genre.java

@@ -22,14 +22,34 @@ public class Genre implements Parcelable {
         return id;
     }
 
+    public void setId(String id) {
+        this.id = id;
+    }
+
     public String getName() {
         return name;
     }
 
+    public void setName(String name) {
+        this.name = name;
+    }
+
     public int getSongCount() {
         return songCount;
     }
 
+    public void setSongCount(int songCount) {
+        this.songCount = songCount;
+    }
+
+    public int getAlbumCount() {
+        return albumCount;
+    }
+
+    public void setAlbumCount(int albumCount) {
+        this.albumCount = albumCount;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

app/src/main/java/com/cappielloantonio/play/model/Queue.java

@@ -1,13 +1,11 @@
 package com.cappielloantonio.play.model;
 
-import androidx.annotation.NonNull;
 import androidx.room.ColumnInfo;
 import androidx.room.Entity;
 import androidx.room.PrimaryKey;
 
 @Entity(tableName = "queue")
 public class Queue {
-    @NonNull
     @PrimaryKey
     @ColumnInfo(name = "track_order")
     private int trackOrder;

app/src/main/java/com/cappielloantonio/play/model/Server.java

@@ -114,6 +114,7 @@ public class Server implements Parcelable {
         return serverId.hashCode();
     }
 
+    @NonNull
     @Override
     public String toString() {
         return serverId;

app/src/main/java/com/cappielloantonio/play/model/Song.java

@@ -3,6 +3,8 @@ package com.cappielloantonio.play.model;
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import androidx.annotation.NonNull;
+
 import com.cappielloantonio.play.subsonic.models.Child;
 
 import java.time.Instant;
@@ -296,6 +298,7 @@ public class Song implements Parcelable {
         return id.hashCode();
     }
 
+    @NonNull
     @Override
     public String toString() {
         return id;