add new rust interface

Part of the currently ongoing overhaul in the experiment control architecture. The interface to Entangleware Control has already been updated; interfaces to the other devices we use around the lab will be updated soon as well and merged into their respective repos, at which point we'll begin to write actual control executables.

Feature parity with the Python version has not yet been reached since the Controller trait does not yet have the ability to run multiple actions in parallel, but since we don't currently do anything that requires it, we can save that implementation for later.