Support no-masking extension

I am working with software that has a number of websocket clients ; some on the local machine over local sockets, some over SSL tunnels, some over TCP, etc.

For the clients running in a secure context, I wouldn't mind saving a few CPU cycles by skipping the standard websocket masking. What I want is perfectly covered by a draft RFC, and I was wondering if this would be interesting to Boost.Beast.

I could try to make a PR at some point, but won't bother if there's no interest in the feature from core developers. =)

https://datatracker.ietf.org/doc/draft-damjanovic-websockets-nomasking/

Start by reading the linked no-masking draft RFC and the existing Boost.Beast WebSocket masking implementation. Determine the protocol, API, compatibility, and security implications for local sockets, SSL tunnels, and TCP clients. Done means the feature scope and supported usage are agreed with the core developers, with tests covering the negotiated no-masking behavior.

Written by the indexing model from the issue text.