Update docs/configuring-playbook-prometheus-nginxlog.md: move sections related to configuration to the dedicated one

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-playbook-prometheus-nginxlog.md

@@ -22,28 +22,7 @@ Add the following configuration to your `inventory/host_vars/matrix.example.com/
 matrix_prometheus_nginxlog_exporter_enabled: true
 ```
 
-### Extending the configuration
-
-There are some additional things you may wish to configure about the component.
-
-Take a look at:
-
-- `roles/custom/matrix-prometheus-nginxlog-exporter/defaults/main.yml` for some variables that you can customize via your `vars.yml` file
-
-## Installing
-
-After configuring the playbook, run it with [playbook tags](playbook-tags.md) as below:
-
-<!-- NOTE: let this conservative command run (instead of install-all) to make it clear that failure of the command means something is clearly broken. -->
-```sh
-ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start
-```
-
-The shortcut commands with the [`just` program](just.md) are also available: `just install-all` or `just setup-all`
-
-`just install-all` is useful for maintaining your setup quickly ([2x-5x faster](../CHANGELOG.md#2x-5x-performance-improvements-in-playbook-runtime) than `just setup-all`) when its components remain unchanged. If you adjust your `vars.yml` to remove other components, you'd need to run `just setup-all`, or these components will still remain installed. Note these shortcuts run the `ensure-matrix-users-created` tag too.
-
-## Docker Image Compatibility
+### Docker Image Compatibility (optional)
 
 At the moment of writing only images for `amd64` and `arm64` architectures are available. The playbook currently does not support [self-building](./self-building.md) a container image on other architectures. You can however use a custom-build image by setting:
 
@@ -56,7 +35,7 @@ matrix_prometheus_nginxlog_exporter_docker_image: path/to/docker/image:tag
 
 Metrics and resulting graphs can contain a lot of information. NginX logs contain information like IP address, URLs, UserAgents and more. This information can reveal usage patterns and could be considered Personally Identifiable Information (PII). Think about this before enabling (anonymous) access. Please make sure you change the default Grafana password.
 
-## Save metrics on an external Prometheus server
+### Save metrics on an external Prometheus server (optional)
 
 The playbook will automatically integrate the metrics into the [Prometheus](./configuring-playbook-prometheus-grafana.md) server provided with this playbook (if enabled). In such cases, the metrics endpoint is not exposed publicly — it's only available on the container network.
 
@@ -68,6 +47,27 @@ Whichever way you go with, this service will expose its metrics endpoint **witho
 
 For password-protection, use (`matrix_metrics_exposure_http_basic_auth_enabled` and `matrix_metrics_exposure_http_basic_auth_users`) or (`matrix_prometheus_nginxlog_exporter_container_labels_metrics_middleware_basic_auth_enabled` and `matrix_prometheus_nginxlog_exporter_container_labels_metrics_middleware_basic_auth_users`).
 
+### Extending the configuration
+
+There are some additional things you may wish to configure about the component.
+
+Take a look at:
+
+- `roles/custom/matrix-prometheus-nginxlog-exporter/defaults/main.yml` for some variables that you can customize via your `vars.yml` file
+
+## Installing
+
+After configuring the playbook, run it with [playbook tags](playbook-tags.md) as below:
+
+<!-- NOTE: let this conservative command run (instead of install-all) to make it clear that failure of the command means something is clearly broken. -->
+```sh
+ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start
+```
+
+The shortcut commands with the [`just` program](just.md) are also available: `just install-all` or `just setup-all`
+
+`just install-all` is useful for maintaining your setup quickly ([2x-5x faster](../CHANGELOG.md#2x-5x-performance-improvements-in-playbook-runtime) than `just setup-all`) when its components remain unchanged. If you adjust your `vars.yml` to remove other components, you'd need to run `just setup-all`, or these components will still remain installed. Note these shortcuts run the `ensure-matrix-users-created` tag too.
+
 ## Troubleshooting
 
 As with all other services, you can find the logs in [systemd-journald](https://www.freedesktop.org/software/systemd/man/systemd-journald.service.html) by logging in to the server with SSH and running `journalctl -fu matrix-prometheus-nginxlog-exporter`.