Adds syndicate auto shotguns and improves shotgun ammo

- Stun slugs are now named properly.
- Stun shells now contain 5 beanbag pellets, for riot control, available in the protolathe.
- Dragon's breath shell added, it's an incendiary shell that does less damage but has multiple pellets. Available in the protolathe with syndicate research.
- Shotgun shells have comments if you're ever confused as to what the difference is in them. They currently share shell sprites which I'm sure can be replaced in the future if anyone wants to.
- Bulldog shotgun added. It has gone through many iterations and balance changes, but at the moment it is a compact (fits in backpacks, e-gun weight size) 8 round combat shotgun loaded by default with stun slugs, much like the old e-guns used to.
- E-guns removed from the nuke op locker and replaced with shotguns.
- Shotgun magazines added to uplink for various TC prices. Extremely deadly in the right hands, and more deadly than an e-gun, but a lot more clunky to reload and there is no more potentially limitless ammo using station rechargers. Ammo preservation and careful resource planning is key, but the magazines aren't exactly expensive or anything. Looking for feedback on the prices.

Bulldog shotgun and magazine sprites primarily courtesy of ausops. He does it for free.

Edit: Also I fixed the L6 sprites, apparently having an uppercase "L" broke them. Thanks byond!