Register application/qlog+json and application/qlog+json-seq media types

[LPardue]

We already declare that these types exist and should be used but they aren't registered in https://www.iana.org/assignments/media-types/media-types.xhtml#application. We should follow the process described in the notes section at the top of that page. Note, we probably don't want to define application/qlog since we are serialization format agnostic and need the suffix to identify the actual format.

[LPardue]

This is tightly linked to https://github.com/quicwg/qlog/issues/434. There's no point registering anything until that discussion is resolved.

[LPardue]

Meeting notes: see https://github.com/quicwg/qlog/issues/434