Add a new domain and nginx virtual host at deploys.tvl.fyi, serving out
of a static directory on whitby which is created by systemd-tmpfiles.
This will be used to serve diffs rendered by nix-diff for
pending deploys for whitby
Since this contains stateful data, it is added to the restic backups
on whitby.
Refs: b/110
Change-Id: I5869d40800bbf5fb8fb39878a857f66ff5787830
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3144
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>