DPP: Expose enrollee pubkey hash for identification

DPP: Expose enrollee pubkey hash for identification

Just like with WPA-PSK and keyids it may be desired to identify
connecting clients to provide additional network filtering.

This does:

 - extend DPP_EVENT_AUTH_SUCCESS to expose public
   key hash of the peer so the system can pick it
   up and use for identification later

 - store public key hash in PMKSA from DPP Network
   Intro for later use

 - extend sta mib to print out the dpp_pkhash
   from PMKSA if present

 - extend AP_STA_CONNECTED to include the
   dpp_pkhash from PMKSA if present

Signed-off-by: Michal Kazior <michal@plume.com>