Convert WifiInfo to TransportInfo

Also, deprecate WifiManager.getConnectionInfo() and add a note to
help apps to migrate. The deprecation is purely cosmetic, no plans to
remove any existing functionality from the WifiManager API.

Bug: 162602799
Test: Compiles
Change-Id: I12c473185dc5518f5684e83c2f49e07271738cb5
Merged-In: I12c473185dc5518f5684e83c2f49e07271738cb5