Update to the IANA CoAP Content-Formats Registration Procedures

Update to the IANA CoAP Content-Formats Registration Procedures Linaro IoTconsultancy.nl This document updates RFC7252 regarding the registration procedures for the "CoAP Content-Formats" IANA registry, within the "Constrained RESTful Environments (CoRE) Parameters" registry group. This document also introduces a new column, "Media Type", to the registry. Furthermore, this document reserves Content-Format identifier 64999 for use in documentation.