The alarm syscall is implemented in libtock-rs, but was duplicated here.
This removes the duplicated code and changes the references to point to
libtock-rs directly.
Co-authored-by: kaczmarczyck <43844792+kaczmarczyck@users.noreply.github.com>
The main benefit is that we removed all mentions of "tock" from all
source code that is not `main.rs` or inside `env/`.
This change makes libtock-drivers oblivious to how many endpoints are
supported. The endpoint is now checked a bit later in the stack.
