[Docs] Add docs about data checks

docs/admin/33_data_checks.rst

+Data checks
+================
+
+TBA.
+
+.. _data-checks:
+
+Configure notifications
+-----------------------
+
+In the ``General`` tab of the configuration interface, you can configure
+email notifications for problems detected by the data checks
+
+* General
+
+  * Send emails if data checks detect problems: Enable email notifications
+  * Email recipients for data checks problem emails: Choose recipient persons
+  * Email recipient groups for data checks problem emails: Choose recipient groups