Update [analytics] section to include the ability to set to false (#71473)

* Update [analytics] section to include the ability to set to false

In the follow section: 

https://grafana.com/docs/grafana/latest/setup-grafana/configure-grafana/#analytics

Added a line for 'enabled' under the [analytics] section to include the ability to set to false as this is now a togglable feature.

* Update docs/sources/setup-grafana/configure-grafana/_index.md

* Update docs/sources/setup-grafana/configure-grafana/_index.md

---------

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>
Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

docs/sources/setup-grafana/configure-grafana/_index.md

@@ -514,6 +514,11 @@ Sets a custom value for the `User-Agent` header for outgoing data proxy requests
 
 ## [analytics]
 
+### enabled
+
+This option is also known as _usage analytics_. When `false`, this option disables the writers that read/write from and to the Grafana databases. The default
+value is `true`.
+
 ### reporting_enabled
 
 When enabled Grafana will send anonymous usage statistics to