wifi: Add instance identifier in SoftApInfo/WifiClient and infoList callback

1. The framework need to know the instance of the client connected to
know which instance is idled.

2. The framework need to know the instance of the soft AP info.

3. Add infoList callback support for dual APs mode.

AP+AP Part 5 includes:
1. Support forceClientDisconnect in dual AP mode.
2. Support dual SoftApInfo callback
   a. New callback onInfoListChanged
   b. Add instanceIdentifier in SoftApInfo but it is used only in
   framework.
   c. Add instanceIdentifier in WifiClient but it is used only in
   framework.

Bug: 162686273
Test: FrameworksWifiApiTests
Change-Id: I207831ff15a3044316556d61a72542ff35c94e74