DPP: Auto-generate Initiator bootstrapping info if needed

DPP: Auto-generate Initiator bootstrapping info if needed

Instead of using the all-zeros Initiator Bootstrapping Key Hash when no
local bootstrapping key is configuref for the Initiator, automatically
generate a temporary bootstrapping key for the same curve that the
Responder uses. If the Responder indicates that it wants to do mutual
authentication, provide the URI for the auto-generated bootstrapping key
in the DPP-RESPONSE-PENDING event for upper layers to display the QR
Code.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>