Shotgun nerfs (#8590)

- Bojevic firerate dropped from 3 to 2
- Pellet damage from 13 to 8 (3 shotting players instead of 2 shot)
- Slightly more spread in line with the design doc. Slug spread I made as accurate as an SMG (so not quite full-screen mob hits but pretty close).

Content.Shared/Weapons/Ranged/Components/AmmoComponent.cs

@@ -35,7 +35,7 @@ public sealed class CartridgeAmmoComponent : AmmoComponent
     /// How much the ammo spreads when shot, in degrees. Does nothing if count is 0.
     /// </summary>
     [ViewVariables(VVAccess.ReadWrite), DataField("spread")]
-    public float Spread = 10f;
+    public Angle Spread = Angle.FromDegrees(5);
 
     /// <summary>
     /// How many prototypes are spawned when shot.