Add initial parts for SAE

Add initial parts for SAE

This introduces new AKM for SAE and FT-SAE and adds the initial parts
for going through the SAE Authentication frame exchange. The actual SAE
algorithm and new fields in Authentication frames are not yet included
in this commit and will be added separately. This version is able to
complete a dummy authentication with the correct authentication
algorithm and transaction values to allow cfg80211/mac80211 drivers to
be tested (all the missing parts can be handled with
hostapd/wpa_supplicant changes).

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