Manageability Appendix A.1 is incorrect and should be removed

[DavidSchinazi]

Appendix A.1 of the manageability draft was copy-pasted from a document I wrote and is no longer correct. In particular it assumes that the packet only contains PADDING frames and a single CRYPTO frame with offset 0. That assumption is not guaranteed to hold with modern browsers, so this text will do more harm than good when it becomes an immutable RFC. Since we also have #351, I'd suggest removing Appendix A entirely.