add armor texture provider hook

[asiekierka]

TODO:

• Better interface name?
• Is capturing ItemStack here useful for modders? Do modders realistically vary their armor textures by NBT at any point, often enough to not justify mixing deeper into ArmorFeatureRenderer with a custom renderer? Would simplify the patch not to.

[LemmaEOF]

NamespacedArmorItem fits the guidelines more, since Namespaced is an adjective. I can also see an advantage to NBT for anything dyeable.

[asiekierka]

No, that's the texture. Dyes are handled separately.

Besides, as tradition, I would expect a more complex armor renderer to just inject into renderArmor's HEAD and redirect processing entirely.

[LemmaEOF]

Ah, right, that was just changed. I can see advantages to having NBT access for stuff like IC2's jetpack duct tape, but since that's supposed to be for any armor that'd be better done as a mixin.

[asiekierka]

From discussion on IRC:

• This hook may be best left to just ArmorItem,
• because Mojang generally implements custom renderers via appending them in .addFeature(). For this, an event should be provided (no performance issue - runs only on instantiation).

[asiekierka]

Time to make a new PR.