Expose lazy services to Rust

Expose register_lazy_service to allow a dynamic service to be
registered. Also expose force_lazy_services_persist to allow a process
with lazy services to temporarily prevent itself being shut down.

Bug: 199367367
Test: Run compos_key_cmd to start a VM and exit; VS process is stopped.
Change-Id: Ie26d73ed2a5ed8a9eee04ee1f28c12a3cbea3f1c