[services-lib] Introduce crypto module

Summary:
Introduced a rusty AES256 module with API similar to the one I introduced in web/native for encrypted media.
It's needed for ENG-4812 (next diff).

Test Plan: Unit test, also tested in tne next diff.

Reviewers: michal, tomek, varun, jon

Reviewed By: varun

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D9034