Add app config option to disable "Email was changed by admin" email

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

Author: MorrisJobke

admin_manual/configuration_server/config_sample_php_parameters.rst

@@ -2016,3 +2016,18 @@ which are older then the number of days that is set for ``activity_expire_days``
 	'wnd.logging.enable' => true,
 
 This enables debug logs for the windows_network_drive app.
+
+Settings app
+^^^^^^^^^^^^
+
+If an email address of a user is changed by an admin, then it triggers an email
+to the user that states "Your email address on URL was changed by an
+administrator.". In some cases this should not be triggered, because it was a
+normal maintenance change. To disable this specific email the appconfig option
+``disable_email.email_address_changed_by_admin`` can be set to ``yes``::
+
+	occ config:app:set settings disable_email.email_address_changed_by_admin --value yes
+
+To disable this behaviour change it to any other value or delete the app config::
+
+	occ config:app:delete settings disable_email.email_address_changed_by_admin