Workspace deps were introduced in Rust 1.64. They don't cover all the
cases that Hakari did unfortunately, but they are simpler to maintain,
and they avoid a couple of issues that Hakari had:
- It sometimes made updating dependencies harder due to the locked versions,
so you had to disable Hakari, do the updates, and then re-generate (
e.g. b396313fe5)
- The current Hakari config was breaking AnkiDroid's build, as it was
stopping a cross-compile from functioning correctly.
- Dropped the protobuf extensions in favor of explicitly listing out
methods in both services if we want to implement both, as it's clearer.
- Move Service/Method wrappers into a separate crate that the various
clients can import, to easily get at the list of backend services and
their correct indices and comments.
