New: Calculate custom formats on demand

src/Radarr.Http/REST/RestResource.cs

@@ -5,7 +5,7 @@ namespace Radarr.Http.REST
     public abstract class RestResource
     {
         [JsonProperty(DefaultValueHandling = DefaultValueHandling.Ignore)]
-        public int Id { get; set; }
+        public virtual int Id { get; set; }
 
         [JsonIgnore]
         public virtual string ResourceName => GetType().Name.ToLowerInvariant().Replace("resource", "");