Upgrades iroh/iroh-relay across datastore, distribution, node, and integration,
adapts iroh_driver to the new Endpoint::builder(Minimal).relay_mode(...) API, and
removes the vendored ed25519-dalek patch now that 0.98 resolves the upstream compile
errors. Adds the SIM_SPEC.md simulator MVP spec under pipeline-parallel-inference.
Signed-off-by: Zachery Aaron Shores-Chmielewski <zacheryasc@gmail.com>
