Move bevy_mikktspace out of tree

[atlv24]

Objective

• Have safe bevy_mikktspace by landing Refactor bevy_mikktspace to entirely safe rust #9050
• Don't have C in-tree

Related issues and PRs:

• Closes Refactor bevy_mikktspace to entirely safe rust #9050
• Closes bevy_mikktspace: crash 'attempt to subtract with overflow' #8429
• Fixes Improve safety of bevy_mikktspace #7372

Solution

• Rebase to main
• Remove glam dependency so lock-step update is not necessary anymore
• Make it standalone: https://github.com/atlv24/bevy_mikktspace
• Transfer to bevy org

Testing

• Test suite made by Layl

[alice-i-cecile]

I like this direction. Strongly in favor of:

1. Not using glam in this, to make it more stable
2. Swapping to the safe version by @LaylBongers
3. Moving it out of our main repo, for both easier independent use and simplified contributions

I'd like to get SME-Rendering sign-off, and figure out our publishing strategy.

[atlv24]

I would suggest publishing it at 0.17, letting it sit for a release or two, and if no issues then publishing 1.0 and forgetting about it for the rest of time

[atlv24]

bevyengine/bevy_mikktspace#1

[tychedelia]

Ty for taking this on!

[atlv24]

bushrat had opinions on how to handle no_std/libm stuff and the api surface of it, so i'd like to hear from him before merge

[mweatherley]

Seconding Alice's comment that avoiding a glam dependency is a good idea (so that it can never be touched again for eternity, or ideally multiple eternities)

[bushrat011899]

Absolutely in favour of this direction. I have a PR here which makes the new crate totally independent of std and even libm, while also removing about a third of the total Rust code and being (IMO) much easier to read.

Additionally, I have another PR here which removes the binary blobs and all C code, instead using mikktspace-sys to provide live A/B comparison when in a #[cfg(test)] environment.

I could pretty easily see the new bevy_mikktspace hitting 1.0 before the end of the year and just not being worried about possibly ever again.

[LaylBongers]

Glad to see this moving forward 🎉, feel free to ping me on discord (or here) with any questions about my original port or the safe conversion. It's been a while but I'm sure I can still answer the trickier details.