Add APIs for Contexthub NAN support

With current hardware limitations, WiFi chips are unable to support NAN
session initialization without assistance of the WiFi framework.

Update the Contexthub HAL APIs to allow Contexthubs to request the
framework enable a NAN session on their behalf so they can make low
power NAN requests to the initialized session without waking the main
CPU.

Bug: 229888878
Test: Update Contexthub HAL
Change-Id: I47a6a1b0512099727c7343542c2aff814dc0d59a