[AWARE] Remove Publish/Subscribe Count configuration

Simplify API: semantics of publish/subscribe count restrictions
aren't clear at the app level. They depend on DW configuration as
well as discovery session type - number of packets transmitted over
the air.

There's already an app-facing discovery session lifetime configuration -
the TTL. That has clearer semantics and is sufficient (for now).

Bug: 36446307
Test: unit tests and integration (sl4a) tests.
Change-Id: I9129975bd2e1a61b3d23a4b6acaae703b42216c7