SupplicantIfaceHal: ISupplicant add/remove interface

1.1 version of supplicant HAL brings in the support for adding/removing
interfaces dynamically. So, make changes in the framework initialization
sequence to use these new methods instead of the older iface retrieval
mechanism.  Since framework needs to be backward compatible, we need to
retain the old mechanism for any devices running the 1.0 version of
supplicant HAL.

These changes apply for both StaIfaceHal & P2pIfaceHal.

Bug: 65673678
Test: Unit tests.
Test: Manual tests by modifying the .rc file to start wpa_supplicant
with no interfaces.
Test: Will send for regression tests.

Change-Id: I666cc95248704bc788e046165601fd312d161b03
6 files changed