Many of the aircraft that we use for DEAD are not actually capable of
the SEAD task in DCS, so they were being loaded as some other task type,
usually one that doesn't support Attack Group, which made them lose
their waypoint actions and do nothing.
This switches them to using CAS which supports a superset of the SEAD
capable aircraft.
I've also audited the SEAD/DEAD lists. The F-117 was removed because it
is not capable of Attack Group *at all*, and all the non-SEAD aircraft
that are capable of ground attack moved from SEAD to DEAD.
Fixes https://github.com/dcs-liberation/dcs_liberation/issues/1086