MediaTypeViewResult formatter does not support header values with quality parameter

[benfoster]

A MediatypeViewResultFormatter with supported media type text/html should handle text/html;q=0.7.

Ideally we would parse the quality value but as a minimum should change the matching logic to use string.contains:

var supportedMediaType = SupportedMediaTypes.Any(
      mt => acceptTypes.Any(at => at.Contains(mt, StringComparison.OrdinalIgnoreCase)));

We also need to provide a default formatter or at least return a 415 (unsupported media type) if none of the formatters are matched.