Add spec for AutoNAT

[yusefnapora]

The AutoNAT service doesn't have a spec yet, so we should write one :) We should also spec out the client side of AutoNAT as well, and perhaps speak to how it fits in with the AutoRelay feature.

@jacobheun has started looking into the js implementation - if you come up with any useful notes drop them in this issue please!

[jacobheun]

I'll take this on. I got a bit consumed by some recent events, but should be able to put a draft together of the spec soon.

[yusefnapora]

Sweet, thanks Jacob 💯

[mxinden]

I'll take this on. I got a bit consumed by some recent events, but should be able to put a draft together of the spec soon.

@jacobheun I am guessing that you are no longer working on this? If so, could you un-assign yourself?

[jacobheun]

@mxinden that's correct, updated.