Adding rust wrapper lib for libfakeServiceManager

rust lib which setup libfakeservicemanager and sets it as default
is being added here. It uses c++ backend underneath.

Test: m libfakeservicemanager_rs
Test: atest fakeservicemanager_test
Bug: 296909761
Change-Id: Ia1e7ebe5174f05fb4f8673a2feaad9b1171eb60c