Update documentation for Pages administration

Update documentation for GitLab Pages administration to include
a section about using API-based configuration.
Includes steps to disable this feature introduced via this [Pages MR](
https://gitlab.com/gitlab-org/gitlab-pages/-/merge_requests/264)
and [Omnibus MR]
(https://gitlab.com/gitlab-org/omnibus-gitlab/-/merge_requests/4057)

Add sync secrets section to pages admin

doc/administration/pages/index.md

@@ -455,9 +455,36 @@ You can run the GitLab Pages daemon on a separate server in order to decrease th
 
 To configure GitLab Pages on a separate server:
 
+DANGER: **Danger:**
+The following procedure includes steps to back up and edit the
+`gitlab-secrets.json` file. This file contains secrets that control
+database encryption. Proceed with caution.
+
+1. On the **GitLab server**, to enable Pages, add the following to `/etc/gitlab/gitlab.rb`:
+
+   ```ruby
+   gitlab_pages['enable'] = true
+   ```
+
+1. Optionally, to enable [access control](#access-control), add the following to `/etc/gitlab/gitlab.rb`:
+
+   ```ruby
+   gitlab_pages['access_control'] = true
+   ```
+
+1. [Reconfigure the **GitLab server**](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the
+   changes to take effect. The `gitlab-secrets.json` file is now updated with the
+   new configuration.
+
+1. Create a backup of the secrets file on the **GitLab server**:
+
+   ```shell
+   cp /etc/gitlab/gitlab-secrets.json /etc/gitlab/gitlab-secrets.json.bak
+   ```
+
 1. Set up a new server. This will become the **Pages server**.
 
-1. Create an NFS share on the new server and configure this share to
+1. Create an [NFS share](../high_availability/nfs_host_client_setup.md) on the new server and configure this share to
    allow access from your main **GitLab server**. For this example, we use the
    default GitLab Pages folder `/var/opt/gitlab/gitlab-rails/shared/pages`
    as the shared folder on the new server and we will mount it to `/mnt/pages`
@@ -481,6 +508,15 @@ To configure GitLab Pages on a separate server:
    gitlab_rails['auto_migrate'] = false
    ```
 
+1. Create a backup of the secrets file on the **Pages server**:
+
+   ```shell
+   cp /etc/gitlab/gitlab-secrets.json /etc/gitlab/gitlab-secrets.json.bak
+   ```
+
+1. Copy the `/etc/gitlab/gitlab-secrets.json` file from the **GitLab server**
+   to the **Pages server**.
+
 1. [Reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
 
 1. On the **GitLab server**, make the following changes to `/etc/gitlab/gitlab.rb`:
@@ -500,61 +536,6 @@ configuring a load balancer to work at the IP level, and so on. If you wish to
 set up GitLab Pages on multiple servers, perform the above procedure for each
 Pages server.
 
-### Access control when running GitLab Pages on a separate server
-
-If you are [running GitLab Pages on a separate server](#running-gitlab-pages-on-a-separate-server),
-then you must use the following procedure to configure [access control](#access-control):
-
-1. On the **GitLab server**, add the following to `/etc/gitlab/gitlab.rb`:
-
-   ```ruby
-   gitlab_pages['enable'] = true
-   gitlab_pages['access_control'] = true
-   ```
-
-1. [Reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the
-   changes to take effect. The `gitlab-secrets.json` file is now updated with the
-   new configuration.
-
-   DANGER: **Danger:**
-   The `gitlab-secrets.json` file contains secrets that control database encryption.
-   Do not edit or replace this file on the **GitLab server** or you might
-   experience permanent data loss. Make a backup copy of this file before proceeding,
-   as explained in the following steps.
-
-1. Create a backup of the secrets file on the **GitLab server**:
-
-   ```shell
-   cp /etc/gitlab/gitlab-secrets.json /etc/gitlab/gitlab-secrets.json.bak
-   ```
-
-1. Create a backup of the secrets file on the **Pages server**:
-
-   ```shell
-   cp /etc/gitlab/gitlab-secrets.json /etc/gitlab/gitlab-secrets.json.bak
-   ```
-
-1. Disable Pages on the **GitLab server** by setting the following in
-   `/etc/gitlab/gitlab.rb`:
-
-   ```ruby
-   gitlab_pages['enable'] = false
-   ```
-
-1. [Reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
-
-1. Copy the `/etc/gitlab/gitlab-secrets.json` file from the **GitLab server**
-   to the **Pages server**.
-
-1. On your **Pages server**, add the following to `/etc/gitlab/gitlab.rb`:
-
-   ```ruby
-   gitlab_pages['gitlab_server'] = "https://<your-gitlab-server-URL>"
-   gitlab_pages['access_control'] = true
-   ```
-
-1. [Reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
-
 ## Backup
 
 GitLab Pages are part of the [regular backup](../../raketasks/backup_restore.md), so there is no separate backup to configure.