Add documentation for admin right privilege setting

Signed-off-by: Carl Schwan <carl@carlschwan.eu>

admin_manual/configuration_server/admin_delegation_configuration.rst

@@ -0,0 +1,27 @@
+======================
+Admin right priviledge
+======================
+
+By default only members of the admin group can access and edit the admin
+settings. It is sometimes needed to give some group of users access to a
+setting page while not giving them access to everything. For this you can
+use the *Admin right priviledge* settings.
+
+.. note::
+  Not every setting pages support this features. This is due to either the
+  feature not being implemented yet for the specific setting page or due
+  to possible priviledge escalations.
+
+Configuring Admin right priviledge
+==================================
+
+Go to the *Admin right priviledge* Admin page, you should be presented
+with the list of settings that support this features.
+
+.. figure:: images/admin-right.png
+
+By clicking on the combobox, you will be able to choose which user groups
+are able to access the selected setting. You can revoke the access at any
+time by removing the group from the selection.
+
+

admin_manual/configuration_server/index.rst

@@ -21,5 +21,6 @@ Nextcloud configuration
    automatic_configuration
    theming
    oauth2
+   admin_delegation_configuration
 
 .. Intentional disabled antivirus_configuration