[CLOSED PR] Kinetics improvements & magazines

[Katzen]

Mmm, overall I don't personally see the need to de-abstract this - while the current implementation is, well, abstract and gamey, this is a video game (and even most shooters treat ammunition as just an invisible bucket of bullets that you shopvac out of corpses) and imo we're not really a game about guns to the extent that justifies realistic magazine handling etc.

Don't want to give TDHooligan dev opinion whiplash but I am in favor of this PR.

I agree that we shouldn't go tactical realism direction but disagree that we should leave the system as-is. We end up with some weird logic situations and bugs right now by treating everything as top up reloads.

I don't feel that this would complicate things for players that much, kinetic weapons with this change are functionally identical until you have performed partial reloads with all your fresh magazines. You both have to survive/shoot this long and be a bit reload happy to get in this situation, which I think can be adequately resolved by allowing magazines to be topped up outside the weapon.

Overall I think:
* Magazine fed weapons should reload by magazine swaps and not the current top up.
* Non magazine weapons should still be topped up like the current system (unless there are good reasons to use the same swapping).
* Partially loaded magazines should top up by clicking them together in inventory.
* There is no need for loose ammo with magazine weapons. Ammo should not be removable from magazines.
* Loose ammo is OK for non magazine weapons but should just be to avoid creating speedloaders/clips from thin air.
* No mixed ammo. Would make things more complicated and possible balance issues.