libbinder: build on Trusty

Adds a new trusty/ subdirectory containing all the files
needed to build Binder RPC on Trusty, including:
* A RpcServerTrusty class used to create Trusty Binder services
* The underlying RpcTransportTipcTrusty transport that interfaces
  between libbinder and TIPC
* Trusty implementations of some OS-specific functionality, like logging
* Make-based build file for libbinder in the Trusty build system

Bug: 224644083
Test: build Trusty
Change-Id: I25b97736d41489d20c2dd266e8e110764215378c