hotspot2: add support for complete PerProviderSubscription/Credential subtree

Added missing fields in Credential subtree for supporting Release 2
and added parsing support for the new fields.

Bug: 34198926
Test: frameworks/base/wifi/test/runtests.sh
Change-Id: Ic3665c963ab77ddc4b9a03262517a3c7a4ec3ffc
5 files changed