Merge changes I026cd52c,Ic378bd76,I373c9a0f

* changes:
  hotspot2: save and load Passpoint configurations to/from config store
  hotspot2: add config store data for Passpoint
  hotspot2: add utility class for XML serialization of Passpoint configurations
tree: c228504733207b8b91bcc228e86536eb63d375f2
  1. libwifi_hal/
  2. libwifi_system/
  3. service/
  4. tests/
  5. PREUPLOAD.cfg