Make `rayon` dependency optional?

[CGMossa]

Is it possible to make rayon-dependency optional? If so, would you consider accepting a PR that does this?

[sarah-quinones]

is there a reason for this?

[CGMossa]

None in particular, just

• Fewer dependencies initially when working with faer,
• Perhaps an expectation since everyone does it?
• For small enough matrices, I'm not sure rayon is even important anyways, even
  though this is supposed to be used with big-stuff.

[sarah-quinones]

fair enough. i'll make it optional (enabled by default) then

[CGMossa]

Thanks! Note, you don't have to do everything. I thought I'd ask first. Then maybe attempt to do it. But of course it would be "easiest" if you did it.

[sarah-quinones]

merged in #73