Create WifiAnnotations and jarjar into framework

@IntDef annotations defined in the Wifi module are
@hide and cannot be referenced from the rest of
framework. Create a separate class for Wifi
annotations that can be jarjar'ed into external
clients.

Bug: 140299412
Test: compiles
Change-Id: I5beac976b4d12fb2c01f46cb46f9c54ab54618ea