Implement RFC 8489

[ernado]

https://tools.ietf.org/html/rfc8489

Standard is already available and can be implement in this package.

[stv0g]

Here is a list of changes since RFC5389 which need to be implemented:

• Added support for DTLS-over-UDP RFC6347.
• Made clear that the RTO is considered stale if there are no transactions with the server.
• Aligned the RTO calculation with RFC6298.
• Updated the ciphersuites for TLS.
• Added support for STUN URI RFC7064.
• Added support for SHA256 message integrity.
• Updated the Preparation, Enforcement, and Comparison of Internationalized Strings (PRECIS) support to RFC8265.
• Added protocol and registry to choose the password encryption algorithm.
• Added support for anonymous username.
• Added protocol and registry for preventing bid-down attacks.
• Specified that sharing a NONCE is no longer permitted.
• Added the possibility of using a domain name in the alternate server mechanism.