This commit adds a multitude of new extension types that were added in
the last few years; it also adds grease values to extensions, curves,
and ciphersuites.
Furthermore, it adds a test that contains a encrypted-client-hello
key-exchange (which uses several extension types that we do not have in
our baseline so far).
DTLSv1.3 changes the DTLS record format, introducing a completely new
header - which is a first for DTLS.
We don't currently completely parse this header, as this requires a bit
more statekeeping. This will be added in a future revision. This also
also has little practical implications.
