Add GitLab.com email sending info to webpage
add IP, domain (mg.gitlab.com) and rDNS (mentioned in ZD 11801) to about.gitlab.com/gitlab-com
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
add IP, domain (mg.gitlab.com) and rDNS (mentioned in ZD 11801) to about.gitlab.com/gitlab-com