Clean up this header file...

use CTASSERTs now that we have them...

Replace a draft w/ RFC that's over 10 years old.

Note that _AALG and _EALG do not need to match what the IKE daemons
think they should be.. This is part of the KABI... I decided to
renumber AESCTR, but since we've never had working AESCTR mode, I'm
not really breaking anything.. and it shortens a loop by quite
a bit..

remove SKIPJACK IPsec support... SKIPJACK never made it out of draft
(in 1999), only has 80bit key, NIST recommended it stop being used
after 2010, and setkey nor any of the IKE daemons I checked supported
it...

jmgurney/ipsecgcm: a357a33, c75808b, e008669, b27b6d6

Reviewed by: gnn (earlier version)