Compress CFrames using axis-angle representation

[Tazmondo]

Effectively halves the size of CFrames from 12 f32s down to 6 f32s.

Does not deal with non-orthogonal CFrames but this is not really a big issue as discussed in the discord channel.

EDIT: For future readers, I'll explain the reasoning behind this.

• Non orthogonal CFrames can only really be made using the specific CFrame.new constructor where you specify every element of the matrix, or with CFrame.fromMatrix. Most users will never use these constructors as they are only used when doing complex math. They can also come about from accumulated error, but correcting that is probably for the best anyway.
• Furthermore, the use of non orthogonal CFrames are extremely limited - apparently being used mostly for skewing cameras. These use cases are rarely, if ever, going to require networking of the skewed CFrame.
• And finally, as documented here, Add description for CFrame rotational data Data-Oriented-House/Squash#28, for the squash library, Roblox itself seems to orthonormalize CFrames before being passed over the network anyway. So, Zap isn't missing any features from Roblox's implementation anyway.

Please review harshly, I am still not super fluent with Rust so I don't know the common patterns and what good, clean, Rust code looks like.

Credits to @aidan-epperly for the idea of using axis-angle representation to compress the rotation data, as well as for giving advice on implementation and possible edge cases.

[sasial-dev]

As discussed on Discord:

[sasial-dev]

Some initial comments

[sasial-dev]

LGTM!

[Tazmondo]

adding docs don't merge yet