Texture from raw

[InfiniteCoder01]

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I was still doing my geng-gltf library development (which is almost done, check it out on github), and when I was doing materials, I've stumbled upon a need to create image from raw data of different formats

Because I've made a mistake when creating branch, to merge requires merging #80 first.

If you are having merge problems regarding crates/ugli-raw/src/gl/constants.rs or crates/ugli/src/texture/mod.rs, use code from my main

[InfiniteCoder01]

If you are having merge problems regarding crates/ugli-raw/src/gl/constants.rs or crates/ugli/src/texture/mod.rs, use code from my main