KTX2 LUT texture

[expenses]

Hi! I was experimenting with https://github.com/expenses/ktx2-tools and thought I'd cook up a KTX2 version of the LUT texture as that might be more usable for some folks. I supercompressed it with Zstandard so it's a little bit smaller (354092 bytes vs 442368). I skipped out on adding a full data format descriptor section to the file as that's the part of the KTX2 spec I don't really get but most readers should be okay with that.

tony-mc-mapface.ktx2.zip