Add Siege Engine sheets

[orffen]

Siege Engines

All of the below are relevant:

• Rate of Fire
• Attack Penalty (already in the base template as attackBonus)
• Damage
• Short Range
• Medium Range
• Long Range

Target AC

• Because Stronghold target AC changes based on how many shots a siege engine takes at it, we want this in the sheet as well
• Set this as a data-target-number to allow rolling this attack automatically (add an icon as well)
• Should add selectable range as well then (radio so that only one can be selected)