implement rama-stun (client+server)

[GlenDC]

• core rfc: https://datatracker.ietf.org/doc/html/rfc3489
• rfc with updates: https://datatracker.ietf.org/doc/html/rfc5389

[GlenDC]

Not available for pickup, this is to be done later. For now not a priority.
If your company or commercial org relies on this, contact us and we can get it arranged to be implemented with the required priority in mind.