Civilian Magazine Spawn Adjustments

[Holli-Git]

Summary

Content "Overhauls magazine spawning"

Purpose of change

This PR is waiting on approval from reviewers

Currently, magazines were spawned in a very messy, inaccurate way. It was just a big list magazines with no guidelines, and was separated into pistol/rifle instead of by caliber. This causes issues as instead of having magazines spawn in a close-enough ratio to guns, it is completely random. It's also a lot harder to contribute guns with magazines, as trying to figure out how common a magazine should be relative to something else is a lot more difficult.

Describe the solution

A) Makes magazine spawns weighted by caliber, and then magazines by caliber weighted by the guns that use them, using gunbroker for this information. Not perfect, but it's the best we got.
B) Culls the magazine lists, a lot of them were unused, or so niche that it could be replaced without any consequences on logic or gameplay.
C) Removes rare magazine itemgroups. This is because what is rare is very hard to determine, and since it was spawned at roughly 2:1 for common to rare magazines, rare magazines weren't all that rare. By combining the rare magazines into the main group, there is no need to separately list what a rare magazine is, instead letting it be actual chance to find a rare mag.

Describe alternatives you've considered

Not doing this

Testing

Additional context

This also necessitates a gun spawn revamp and an overlook at guns. For example, browning hi powers are very rare despite them being not too uncommon.