[DONE][Suggestion] Color facing indicators by faction

[Zesty]

Rarely, mods will have missions with the same types of both allied and enemy units running around. This can make it really hard to distinguish friend from foe, especially when they are all ontop of each other. If you want an example try the Ancient Mummy Abode mission in Xcomfiles. My idea is to color the facing indicators you get by pressing alt depending on whether they are friend or foe. Keep the current white for Xcom units, make it red for enemies and green for friendlies.

[Yankes]

This is probably doable with scripts, as they now have access to pressed `alt` and to what faction given unit belong.

[Meridian]

Keep the current white for Xcom units, make it red for enemies and green for friendlies.

Xcom in TFTD is green.
(Unless you change the resources in DETBLOB.DAT)
So green cannot be used for neutrals (which you call friendlies), because it is already used for friendlies/allies.

TFTD doesn't have a red color range, the best I can do is "dirty orange".

To make it at least a bit compatible with the minimap colors, I suggest blue for enemies, red/orange for neutrals, white/green for friendlies.

[Meridian]

Done.

https://github.com/MeridianOXC/OpenXcom/commit/a502ed04a754e2f5aaa727db9b20318c4b19552e