[FEATURE] emissive support

[HazeWorksOnFiveMServer]

Hey I was wondering if there is a way to implement Optifine's Special Format (texture_e.png) so that DynamicAssetGenerator can generate them itself and not needed to be handmade. In the case of Excavated Variants Repo. would be around 1407 pictures that would need to be manually made and edited to get that _e Special Format working so that shaders or just users that use third party mods can use them.

[HazeWorksOnFiveMServer]

This would fix this Issue

[lukebemish]

I'm lumping this in with #57; I may get around to it eventually, but it's low priority and Optifine's format is not super well documented, frankly.

[HazeWorksOnFiveMServer]

If its just ores I can tell you what pixels need to get generated and you implement that with ease