Define golden anvil ItemStacks, add/hook crafting recipes

*Defines ItemStacks for Golden Anvils, Slightly Damaged Golden Anvils, and Very
 Damaged Golden Anvils
*Defines crafting recipe for Golden Anvils
*Hooks crafting recipe into the server in onEnable
*Adds removal of crafting recipe in onDisable

Change-Id: I3b4c662616ae981e650ea64673ef8007124f6bd7