Rebalances the shotguns

With some major tweaks: * Enable the shotgun from the start instead of requiring Military technology * Moves piercing shotgun shells from Military 4 to Military 2 technology

With a few minor tweaks: * Adds a minor damage and shooting speed boost increase to Military 4 * Reduced the movement penalty from firing shotguns, combat shotguns penalty is reduced to 40% from 50% while the normal shotguns penalty duration is halved * Reduced the magazine capacity of shotgun shells from 10 to 6 * Increase the damage of piercing shotgun shells to 10 per pellet, for a total of 160 damage per shot * Increase the range of piercing shotgun shells from 15 tiles to 17 tiles * Adds piercing to piercing shotgun shells so they sometimes shoot through enemies

Vanilla rebalance

FFF-427 promised some combat balance tweaks, upping the damage of shotgun shells from 5 to 8 per pellet.
This is in turn made piercing shotgun shells almost obsolete as they retained the 8 damage per pellet and 16 pellet vs 12 pellet is minor when thinking about the cost difference between them.

So this mods make piercing shells more enticing by adding piercing, upping the damage and range, while also reducing the magazine size of normal shells.

Uranium shotgun shells

[Optional] mod dependency, which is yet to be updated from 1.1

• Increased the cost of Uranium shotgun shells by 1 piercing shotgun shell
• Increased the magazine capacity of Uranium shotgun shells from 10 to 14
• Increased the pellet damage of Uranium shotgun shells from 12 to 18