Move postfix installation to a separate page
We should move the postfix/sendmail installation instructions to a separate page, perhaps updating this page: https://docs.gitlab.com/omnibus/settings/smtp.html
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
We should move the postfix/sendmail installation instructions to a separate page, perhaps updating this page: https://docs.gitlab.com/omnibus/settings/smtp.html