Restricts contents of custom loadout weapon boxes

[doganesi]

About the pull request

Adds a can_hold list to the Type 73 storing case, D18-storing boxx, and the M8 cartridge bayonet packaging.

Explain why it's good for the game

Prevents any unintended use of these items, such as storing 3 medium sized items inside of a single medium size slot within a satchel.

Fixing oversights is good.

Testing Photographs and Procedure

Screenshots & Videos

https://streamable.com/8rh75b

Changelog

🆑
fix: Fixed some oversights with custom loadout provided weapon boxes
/:cl:

[Drulikar]

BTW you don't need to concern yourself with this much nor press it every time. You only need to update with master if master has changes that are relevant to your PR.