Expose gameReviewsSummary as Elide root

Since not every game has a review summary, querying games and sorting
by review score is very inefficient. This way, the review summaries can
be queried directly.

src/main/java/com/faforever/api/data/domain/GameReviewsSummary.java

@@ -16,7 +16,7 @@
 @Entity
 @Setter
 @Table(name = "game_reviews_summary")
-@Include(type = "gameReviewsSummary")
+@Include(rootLevel = true, type = "gameReviewsSummary")
 @Immutable
 public class GameReviewsSummary {
   private int id;