[Wifi][Passpoint] Passpoint Provisioner and APIs

Create the PasspointProvisioner class that will implement the
subscription provisioning flow. Added an API to start subscription
provisioning with a given provider.
This API enforces NETWORK_SETTINGS permission and is a hidden API.
Unit tests for all classes modified and new classes added.

Bug: 67599905
Test: Unit tests
Change-Id: I073c327c1e63030c81ac81124339ee83b590e012
10 files changed