My main workstation is a Thinkpad without a great deal of compute
power available, so enabling the use of whitby as both a substituter
(services.sshServe) and a remote builder (openssh.authorizedKeys) will save me
some time when working on nix things and depot things.
Change-Id: I17bfcbb9860f42fb667603ad819e38e82e6052da
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2399
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Tested-by: BuildkiteCI