Docs: add hidden_users configuration field (#30435)

* Docs: add hidden_users configuration field

* Add feature in the what's new

* Update configuration.md

* apply PR feedback

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* fix what's new link

* Update docs/sources/whatsnew/whats-new-in-v7-4.md

Co-authored-by: Leonard Gram <leo@xlson.com>

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
Co-authored-by: Leonard Gram <leo@xlson.com>

docs/sources/administration/configuration.md

@@ -631,6 +631,10 @@ The duration in time a user invitation remains valid before expiring.
 This setting should be expressed as a duration. Examples: 6h (hours), 2d (days), 1w (week).
 Default is `24h` (24 hours). The minimum supported duration is `15m` (15 minutes).
 
+### hidden_users
+
+This is a comma-separated list of usernames. Users specified here are hidden in the Grafana UI. They are still visible to Grafana administrators and to themselves.
+
 <hr>
 
 ## [auth]

docs/sources/whatsnew/whats-new-in-v7-4.md

@@ -105,6 +105,11 @@ You can lock down what can be done in the frontend code. Lock down what can be l
 
 [content_security_policy]({{< relref "../administration/configuration.md#content_security_policy" >}}) and [content_security_policy_template]({{< relref "../administration/configuration.md#content_security_policy_template" >}}) were added to [Configuration]({{< relref "../administration/configuration.md" >}}) as a result of this change.
 
+### Hide users in UI
+
+You can now use the `hidden_users` configuration setting to hide specific users in the UI. For example, this feature can be used to hide users that are used for automation purposes.
+[Configuration]({{< relref "../administration/configuration.md#hidden_users" >}}) has been updated for this feature.
+
 ### Elasticsearch data source updates
 
 Grafana 7.4 includes the following enhancements