Add realm information for Authenticate API (#3725)

Add realm information for Authenticate API

Author: russcam

src/Nest/XPack/Security/Authenticate/AuthenticateResponse.cs

@@ -3,6 +3,15 @@
 
 namespace Nest
 {
+	public class RealmInfo
+	{
+		[DataMember(Name = "name")]
+		public string Name { get; internal set; }
+
+		[DataMember(Name = "type")]
+		public string Type { get; internal set; }
+	}
+
 	public class AuthenticateResponse : ResponseBase
 	{
 		[DataMember(Name = "email")]
@@ -21,5 +30,11 @@ public class AuthenticateResponse : ResponseBase
 
 		[DataMember(Name = "username")]
 		public string Username { get; internal set; }
+
+		[DataMember(Name = "authentication_realm")]
+		public RealmInfo AuthenticationRealm { get; internal set; }
+
+		[DataMember(Name = "lookup_realm")]
+		public RealmInfo LookupRealm { get; internal set; }
 	}
 }