Integrate noise KN

[plopezlpz]

We want to have an easy way to use noise KX to encrypt messages in waku, specially used for inbox chat sdk

(noise is used in nim-libp2p as well)

https://noiseexplorer.com/patterns/KX/

The porpuse is to have this encryption for inbox, inbox flow explained here:
https://github.com/waku-org/nim-chat-poc/blob/main/README.md

[plopezlpz]

@jazzz FYI, is there a spec for inboxes or for now only this readme

[jazzz]

@plopezlpz current WIP spec for inboxes is (https://github.com/waku-org/specs/blob/jazzz/inbox/standards/application/inbox.md) (NB: This currently references the old KN handshake pattern )