Unified ammo/ammuniton, round and bullet spelling

[Faalagorn]

• Ammo/Ammunition is anything that goes to weapon – I reserved the possibility for (especially mods) to have things without case (canons) and magazines that hold bullets directly, including caseless ammunition – that could technically be changed to "round" in occasions we are sure all the things loaded are actual rounds/cartridges (see below), as was the case for old Varmint rifle sound cues: https://en.wikipedia.org/wiki/Ammunition
• Round (cartridge) is for bullet, case, primer and propellant combo, should be adjusted accordingly. I used round when appropriate, I couldn't find the actual "cartridge": https://en.wikipedia.org/wiki/Cartridge_(firearms)
• Bullet when actually bullet is being referenced, e.g. manufactured in molds and in wounds: https://en.wikipedia.org/wiki/Bullet

[Faalagorn]

Follow up to this issue, the main issue about ammunition/ammo vs round now is I guess for mods, most notable crossbow mods where you currently load "rounds" (or even worse, "bullets") into it.

If Crossbow is planned to be implemented as a separate entry later on, for example at or after the hunting update, we can skip Ammunition parts and just use Round for the most part. The most important changes right now is getting rid of stuff like Insert %1 Bullets in Magazine, Bullet in Rifle and Load Bullets into\nspare Magazine and Bullets Ammo Strap ;)

Let me know if you want to split it into two different PRs, one fixing just those issues and another one fixing the rest @nsKpz !