Implement #474 and add a 'multitool' item type

[AnAwesomGuy]

Description

This PR fixes #474 and adds a new item type, 'multitool'. To create a multitool, set the item type to 'multitool' and use .tool(toolName) to add a tool to the multitool. Valid tool types include: 'axe', 'hoe', 'pickaxe', and 'shovel'.

Example Script

// priority: 0
StartupEvents.registry('item', event => {
    event.create('axe_shovel', 'multitool').tool('axe').tool('shovel').maxDamage(172)
    event.create('pickaxe_axe', 'multitool').tier('diamond').tool('axe').maxDamage(140).tool('pickaxe')
    event.create('iron_paxel', 'multitool').tool('pickaxe').tool('axe').tool('shovel').tool('hoe').maxDamage(64)
})

[ChiefArug]

Another thing to consider is Forges ToolAction system. It would require a subclass for Forge tho.

[AnAwesomGuy]

i think its good now!