Initial Binder Rust crate

This crate exposes an idiomatic Binder interface for Rust clients and
services. This interface is primarily designed for use by the
forthcoming Rust backend for the AIDL compiler. The crate links against
the stable NDK version of the libbinder interface and therefore can
be used by APEX packages.

Test: atest rustBinderTest libbinder_rs-internal_test
Bug: 161559357
Change-Id: I2e9b800186f24217edeb1c3778f13902a3cca2fd