Automatically resize images to fit limits (#831)

Resize images for Avatars, Worlds, Gallery, Icons and Emojis when uploading if it exceeds VRChats limits (2000 pixels in any dimension and 10MB file size).

Dotnet/WebApi.cs

@@ -217,7 +217,8 @@ namespace VRCX
                 }
             }
             var imageData = options["imageData"] as string;
-            byte[] fileToUpload = Convert.FromBase64CharArray(imageData.ToCharArray(), 0, imageData.Length);
+            byte[] fileToUpload = AppApi.Instance.ResizeImageToFitLimits(Convert.FromBase64String(imageData));
+
             string fileFormKey = "file";
             string fileName = "blob";
             string fileMimeType = "image/png";