Add preliminary support for logging outgoing HTTP requests

PluralKit.Bot/Modules.cs

@@ -94,6 +94,8 @@ namespace PluralKit.Bot
                 Timeout = TimeSpan.FromSeconds(5)
             }).AsSelf().SingleInstance();
             builder.RegisterInstance(SystemClock.Instance).As<IClock>();
+
+            builder.RegisterType<DiscordRequestObserver>().AsSelf().SingleInstance();
         }
     }
 }