Adds US Weapons files with fallbacks in order of capability.
Aim-7P added by ED for several US fighters. Falls back to 7MH, and Aim-120B fallback adjusted from MH to P.
Aim-9J and Aim-9Juli added by ED for the Mirage F-1, also used by F-4 mod and will likely be added to the F-4E whenever it ships. Aim-9J placed between 9P and 9B, Aim-9 Juli placed between 9L and 9P5.
2x9j and 2x9Juli added by VSN for F-4 mod. Placed between 2x versions of same missiles as above.
Aim-7E now falls back to 2xAim9x instead of single Aim9x so that it runs through the entire loop of Aim-9s.
Add Aim-9B's as fallbacks for F-4s and A-4s. Rework path by capability and not year (i.e. Aim-9X>M>L>P5>P>B), leave note in P that the year can be pushed back to represent earlier models the P is based on that are missing from game.
Added weapons fallback data for the laser guided rockets, AIM-54's,
AGM-65 E/F, 4X Hellfire and TOW carried by US helis, rockets for them
to fall back to, all of the USSR IR missiles, R-3R, Mk-83 & Mk-84 and
adjusted the dates for the R-27ER &ET to 1990.
The only parts of the old weapon data that worked well (didn't commonly
result in empty pylons) did this implicitly, so make the grouping
explicit.
This also moves the data out of Python and into the resources, which
both makes the data moddable and isolates us from a huge amount of
effort and a save compat break whenever ED changes weapon names.
I didn't auto migrate the old data since the old groups were not
explict and there's no way to infer the grouping. Besides, since most of
the weapons were *not* grouped, the old data did more harm than good in
my experience. I've handled the AIM-120 and AIM-7 for now, but will get
at least all the fox 3 missiles before we ship.
