Remove instance logic for BinaryStorage and JsonStorage, part 1

1. part of #389
2. huge refactoring

Wox.Core/UserSettings/HttpProxy.cs

@@ -5,7 +5,7 @@ namespace Wox.Core.UserSettings
     public class HttpProxy : IHttpProxy
     {
         private static readonly HttpProxy instance = new HttpProxy();
-        public UserSettingStorage Settings { get; set; }
+        public Settings Settings { get; set; }
         public static HttpProxy Instance => instance;
 
         public bool Enabled => Settings.ProxyEnabled;