Move FastTransform to webrender_api crate

[nicoburns]

servo-malloc-size-of and servo-geometry are currently depending on webrender because they need the FastTransform type. As these crates are low in the crate graph, this means that ~50 servo crates need to recompile when modifying webrender.

This PR, moves FastTransform into webrender_api which means thatservo-malloc-size-of and servo-geometry can also depend only on webrender_api and the only servo crates that needs to depend on webrender are servo-paint and servo.

Servo PR: servo/servo#45485

[Loirooriol]

It's not a small patch, so I would like to know what @mrobinson thinks about this making future webrender syncs harder or such. Maybe it should land upstream, and then sync? Seems it has been a while.

[nicoburns]

Ah, I had though the FastTransform type was already our downstream patch, but it looks like we just made it public. I can definitely send this upstream if that's preferable.

[nicoburns]

I've sent this upstream as https://bugzilla.mozilla.org/show_bug.cgi?id=2046918. Maybe we can try and include it in the upcoming sync if it lands soon.

[nicoburns]

I think the current state (without this PR) may actually be causing a relatively significant slowdown in clean build times for Servo, because it seems to be serializing the build of WebRender (including it's build script) and script/script-bindings, which both end up being part of the critical path in the build pipeline.

[mrobinson]

We will likely re-sync and re-release soon due to servo/servo#45728, so if you can land this upstream it should be included in the next release.

[nicoburns]

I will try to land upstream soon. Will have to work out why it got rejected by CI last time (I'm currently having trouble with Mozilla try access)