KTX AI module

[MJ]

• Add the new ktx-ai module with a gdxAI dependency to the list of the third-party extensions.
• Update the default KTX version to 1.11.0-rc6.

[Tommy Ettinger]

Oh, I added this myself without seeing this... I'll check that they're equivalent...
Wait, this is an issue, not a PR! I can close this since it's done!

[MJ]

I haven't gotten around to add a PR yet, thanks! :)