Stocks, stock accessories, new C++ handling for Folding Stocks

[bombasticSlacks]

Summary

Content "Folding Stocks that fold on activate, Stock accessories"

Purpose of change

#55428 back-end implementation stuff. Plus the part I want which is functioning folding stocks.

Describe the solution

This PR does the following:

1. Splits Stocks and Stock Accessories.
2. Adds an explicit Handling modifier to stocked guns vs pistols, this was hidden in the C++ but I wanted to make it clearer with a comment.
3. Removes the Stock slot from the bullpup HWP and added an adjustable integrated bullpup stock.
4. Added two new C++ flags, COLLAPSED_STOCK and FOLDED_STOCK. Folded is for guns which the stock folds to the side, reducing length but not volume. Collapsed is for guns like the MP7 where the stock presses into the body saving volume and length.
5. Added transforms and the folded versions to the wire and folding stock
6. Added a high end adjustable folding stock to replace one in CRIT mod (since butt hooks now have their own slot).
7. Added lengths and volumes to things that were missing them like butt hooks.
8. Made it so integral length counts stock and stock accessories separately when calculating gun length
9. Added a name suffix for (folded) to guns so people don't fire their folded guns like dum dums
10. Made the wire stock irremovable since it's exclusively used on guns where it is or at least probably shouldn't be removable and migratable to other guns.
11. Fixed a simple bug with gun mods and transforms not detecting.

Specifically:

• Somehow managed to keep the nebulous system where guns with stocks and without are all handled implicitly without the player thinking about it.
• Butt hooks, and cheek pads are now on a separate slot "stock accessories". I went through and added these slots to every gun that could realistically take em. this is most the churn in this PR
• COLLAPSED_STOCK is a flag that uses the old rules for reducing volume of folded guns. FOLDED_STOCK no longer decreases volume, the stock is still there just folded to the side. However both these flags now reduce 20cm off the length of the gun. Slime in Sawing off weapon stocks and better folding stocks #55428 estimates cut off at 26-24cm. With a folding stock its not as efficient as cutting off since there is either the back of stock still or the joint it folds on.
• Any folded stock gets -10 to handling (reminder stock weapons get 20 handling, pistols get 10)
• Added a non vanilla used high end stock which I'm gonna put on some fancy guns at some point. Currently it replaces a CRIT stock that doesn't make sense now that butt hooks are their own slot.
• Butt hooks are now 4cm of additional length.
• If an item is a gun the game checks if it has either of the added flags and then appends (folded) to it's name to let people play smart.

Describe alternatives you've considered

Adding dispersion changes as well, however this isn't currently handled in game and I didn't want to scope creep anymore.

Adding rules for buffer tube rifles.

Testing

Everything works in game as far as I can see. Gonna get yelled at by generic guns.

Additional context

Collapsed Vs Noncollapsed

Folded Vs Nonfolded

Accessories on a gun

[TheShadowFerret]

Added a name suffix for (folded) to guns so people don't fire their folded guns like dum dums

That sign won't stop me because I can't read! :)

[Faalagorn]

Marked missing apostrophes

[Faalagorn]

items → item's

[Faalagorn]

Also missing comma before "it" (or better yet, ", so it")

[Faalagorn]

I'd also give tag as well while at it.

[Faalagorn]

Finally (sorry about the comment streak); "item" or "gun"? I think there's no other items that can have stocks.

[Faalagorn]

items → item's

[Faalagorn]

Also missing comma before "it" (same as above)