warn about email in the gitlab restore procedure (tpo/tpa/team#40820)

takes a *long* time to start (think minutes)... You can follow its

progress in `/var/log/gitlab/gitlab-rails/*.log`.

That procedure only restores a *part* of the system, namely what is

covered by the nightly backup job. To restore the rest (at the time of

writing: artifacts and repositories, which includes wikis!), you also

need to specifically restore those files from the backup server.

Be warned that the new server *will* start sending email

notifications, for example for issues with an due date, which might be

confusing for users if this is a development server. If this is a

production server, that's a good thing. If it's a development server,

you may want to disable email altogether in the GitLab server, with

this line in `hiera/roles/gitlab_dev.yml` in the `tor-puppet.git`

repository:

    profile::gitlab::app::email_enabled: false

So the above procedure only restores a *part* of the system, namely

what is covered by the nightly backup job. To restore the rest (at the

time of writing: artifacts and repositories, which includes wikis!),

you also need to specifically restore those files from the backup

server.

For example, this procedure will restore the repositories from the

backup server: