[mtl] Refactor ImageLike and image::Kind

[Michael-Lfx]

gfx/src/backend/metal/src/native.rs

Lines 312 to 313 in f820ada

	pub(crate) like: ImageLike,
	pub(crate) kind: image::Kind,

ImageLike and image::Kind imply that they dedicated to describe Image(Texture) type. But they are different of cause. Can you refactor them for better understanding? @kvark

[kvark]

Be my guest if you come up with cleaner names ;)