Rename the org and package restructure (VOTE NOW)

[sipsorcery]

Given there is now more interest and use of the SIPSorcery packages for WebRTC than VoIP I think it's a good time to rename the GitHub organisation and at the same time reorganise the packages.

I've put some options for possible new organsation names in the poll below if anyone wants to vote. Also open to other options.

For splitting up the current SIPSorcery monolithic package I'm thinking:

• WebRTC
• SIP (or VoIP)
• Core (or Net) for everything else. This could be broken down further for things like RTP, ICE, STUN, SDP etc. but that seems like extra work for marginal benefit.

The other SIPSorcery packages would keep their existing names but would exist under the new GitHUb org.