Add API for Wi-Fi STA+STA feature for multi internet.

Wi-Fi feature for STA+STA with multiple internet support.
Add the public API and System API to:
1. Query if Wi-Fi multi internet feature is supported.
2. Set the Wi-Fi multi internet mode to predefined multi internet use
case modes: [disabled, DBS AP, and multi AP].
3. Query the Wi-Fi multi internet feature mode.

Bug: 181741503
Test: atest WifiManagerTest
Change-Id: Ia10214ce6909666eceeca06c1122d8679ea98633
10 files changed