MimeMapping.GetMimeMapping returns wrong mime types

[ngibbonssdl]

The .NET Framework's MimeMapping.GetMimeMapping method used in the DefaultContentProvider is a little out of date when it comes to known MIME types.

WebP images are incorrectly returned with a MIME type of application/octet-stream when it should be image/webp.

Suggest using something like https://www.nuget.org/packages/MimeMapping/ and probably encapsulating this in another interface/service so different providers can be swapped in should needs be.