Face sensing

[GarboMuffin]

Closes #880

Still a lot to do.

• I'm developing against the Scratch Lab version. Not sure if they changed anything in the version that will get released.
• Still need to figure out how large external libraries will be handled. Being forced to figure that out now.
• Need to verify that performance impact is minimal, probably add some throttling to keep in line with the Scratch Lab version.
• Blazeface doesn't directly tell us some things like how titled the head is or where the top is after accounting for rotation. I wrote some of my own estimators for those that seem to closely match Scratch Lab, at least on me.

[GarboMuffin]

For the extra non-script assets that blazeface loads - Not clear what we'll do about those since #2267 doesn't plan to include anything. For now I'll probably put a copy of them on packagerdata.turbowarp.org and hardwire the desktop app to make this work offline.

[ampelectrecuted]

This should probably be moved into the real VM since the extension is now available in upstream

[GarboMuffin]

it's fine to keep it here. packaging everything so that it can work offline is easier outside of that repository

[GarboMuffin]

we'll do dependencies after. for now i just copied the modules to packagerdata.turbowarp.org so we can get this in quickly without loading scripts from third party