EAP-TEAP server and peer implementation (RFC 7170)

EAP-TEAP server and peer implementation (RFC 7170)

This adds support for a new EAP method: EAP-TEAP (Tunnel Extensible
Authentication Protocol). This should be considered experimental since
RFC 7170 has number of conflicting statements and missing details to
allow unambiguous interpretation. As such, there may be interoperability
issues with other implementations and this version should not be
deployed for production purposes until those unclear areas are resolved.

This does not yet support use of NewSessionTicket message to deliver a
new PAC (either in the server or peer implementation). In other words,
only the in-tunnel distribution of PAC-Opaque is supported for now. Use
of the NewSessionTicket mechanism would require TLS library support to
allow arbitrary data to be specified as the contents of the message.

Signed-off-by: Jouni Malinen <j@w1.fi>