Add 14.0 update page skeleton
Add 14.0 update page skeleton

- To avoid multiple merge requests bringing conflicts, adding the
  skeleton so we are all targeting the same starting point for 14.0

Related https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/5504

Signed-off-by: Robert Marshall <0465b3b4f3ae0103ad50d09ff86a3523700a2979@gitlab.com>

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab