We don't need explicit configuration of initial points. The plane
automatically configures any steerpoint immediately before a target
point as an initial point.
Target offset points and aim points have not been implemented because I
can't find any information the describes their intent.
Fixes https://github.com/dcs-liberation/dcs_liberation/issues/3088.
The old DCS AI F-15E is sticking around because the two have very
different weapon sets for now, so it's probably better to use the AI-
only one for squadrons that don't expect players.
I've avoided renaming the old one (we probably should name it "... (AI)"
for clarity) because the rename will break save compat. I have added a
_new_ name that new campaigns can use though.
https://github.com/dcs-liberation/dcs_liberation/issues/3028
