Add IWifiApIface@1.4 (configurable MAC address)

Mirrors the methods and tests introduced in IWifiStaIface@1.2 and @1.3.

Android.bp generated with
$ hidl-gen -o . -Landroidbp -randroid.hardware:hardware/interfaces android.hardware.wifi@1.4

Bug: 132705022
Test: make vts && vts-tradefed run vts-host --skip-preconditions --primary-abi-only --module VtsHalWifiV1_4Host
Change-Id: Iddacd2770c59522001673d10daafd3bbed3844f6