Add type to externalids to distinguish them in the UI

MediaBrowser.Controller/Providers/IExternalId.cs

@@ -8,8 +8,27 @@ namespace MediaBrowser.Controller.Providers
 
         string Key { get; }
 
+        ExternalIdType Type { get; }
+
         string UrlFormatString { get; }
 
         bool Supports(IHasProviderIds item);
     }
+
+    public enum ExternalIdType
+    {
+        None,
+        Album,
+        AlbumArtist,
+        Artist,
+        BoxSet,
+        Episode,
+        Movie,
+        OtherArtist,
+        Person,
+        ReleaseGroup,
+        Season,
+        Series,
+        Track
+    }
 }