wifi: Use SoftApConfiguration to replace WifiConfiguration for SoftAp

Add new APIs for soft Ap enable/configuration set and get.

Bug: 142752869
Test: atest frameworks/base/wifi/tests/
Test: Manual Test, softAP enable/disable/configuration change.
Change-Id: Ie9c666d6c10d59d53bd75768e9eb2da1de22fb55