Item CustomModelData support

[CamperSamu]

Is your feature request related to a problem?

CustomModelData (coupled with custom fonts) is essential to achieve simple dynamic custom UIs in Minecraft, an essential feature for modern servers trying to deliver a more polished experience to their players.
It also allows for custom item textures and much more by simply adding a NBT tag (eg. {CustomModelData:69420}) to an item coupled with a resource pack with the right model predicate (look at https://minecraft.fandom.com/wiki/Player.dat_format#General_Tags and https://minecraft.fandom.com/wiki/Tutorials/Models#Item_predicates).

Describe the solution you'd like.

It would be useful to have an optional custom-model-data field inside the panel yml for each item entry allowing for setting this NBT.
Handling of the acutal textures is not requried since it's up to the final user to do all the leg work, this request is mainly to allow custom items and pre-baked ui elements to be showed inside panels.

Describe alternatives you've considered.

Someone could use ChestCommands or something like that, but why should we?
BentoBox already has something to handle panels for its plugins, there shouldn't be the need to use something else in this context (aka simple panles).

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 supported BentoBox build or Addons.

Other

From my previous comment on #21:

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Here some example of custom UIs from the Nova plugin and SlimeFun plugin (using the unofficial resource pack for SlimeFun):





(ignore the Italian lol)

[tastybento]

@BONNe what do you think about this?

[BONNe]

It is a todo. Need to rewrite some logic of CP.