title: Servlet 3.0 MultiPartConfig not working for multipart/related
body: <p>I am getting the following exception when trying to use the <code>getParts()</code> method on the <code>HttpServletRequest</code> Object. Here is the <code>request#contentType() = "multipart/related; type="application/dicom"; boundary=multiparttest"</code></p>
  
  <pre><code>ERROR [stderr] (default task-1) javax.servlet.ServletException: UT010016: Not a multi part request
  ERROR [stderr] (default task-1)     at io.undertow.servlet//io.undertow.servlet.spec.HttpServletRequestImpl.loadParts(HttpServletRequestImpl.java:575)
  ERROR [stderr] (default task-1)     at io.undertow.servlet//io.undertow.servlet.spec.HttpServletRequestImpl.getParts(HttpServletRequestImpl.java:514)
  </code></pre>
  
  <p>Almost all of the documentation talks about multipart/form-data. Is multipart/related not supported by <code>MultiPartConfig</code>? What is the best way to procress request with multipart/related content?</p>