[Suggestion] Switch BCLib emission to Minecraft 1.21.4+ Emission

[paulevsGitch]

Description

Minecraft adds new emission to block models format, so the suggestion is to change how BCLib handles emission - instead of overriding shaders it should just automatically add block model parts with proper tags, example:

{
	"from": [ 0.8, 0, 8 ],
	"to": [ 15.2, 16, 8 ],
	"rotation": { "origin": [ 8, 8, 8 ], "axis": "y", "angle": 45, "rescale": true },
	"shade": false,
	"light_emission": 15,
	"faces": {
		"north": { "uv": [ 0, 0, 16, 16 ], "texture": "#cross_e" },
		"south": { "uv": [ 0, 0, 16, 16 ], "texture": "#cross_e" }
	}
}

In that case atlas modification and shaders replacement will be not necessary, additionally emission becomes completely compatible with Sodium, Iris and other mods