Wifi: Introduce additional APIs to support STA + SoftAp concurrency

1. Add a configuration  parameter to indicate STA + SoftAp concurrency support
2. Add new APIs createSoftApInterface/deleteSoftApInterface to create/delete
   an interfcae softap0, an additional interface to cater to STA + SoftAp
   concurrency.
The intention here is to create another SoftAP interface while the
station interface is active, in contrary to the current design in
the framework which shall shut down the station components (wpa_supplicant
/ host driver) on a SoftAp start(starts hostapd the host driver).

Change-Id: Ie613f73b2fd98f02ba0611e9545f6ec749fd2087
CRs-Fixed: 1017907