[ASE-Rewrite] Support for "item_model"

[DreiFxn]

Is your feature request related to a problem?

(Just a QoL for my server to get everything to item_model)

Describe the solution you'd like.

Besides having custom_model_data also implement item_model (new in 1.21.4) to identify items as the ASE Tool

Describe alternatives you've considered.

Using CMD is sometimes abit clunky since it overwrittes stuff, item_model would directly redefine the model of the item.

Agreements

• I have searched for and ensured there isn't already an open issue regarding this.
• I have ensured the feature I'm requesting isn't already in the latest ArmorStandEditor Build.

Other

Tell me if something is missing.