make status dashboard documentation visible and remove umn

Reviewed-by: Gode, Sebastian <sebastian.gode@t-systems.com>
Co-authored-by: tischrei <tino.schreiber@t-systems.com>
Co-committed-by: tischrei <tino.schreiber@t-systems.com>

otc_metadata/data/documents/sd-umn.yaml

@@ -1,9 +0,0 @@
----
-hc_location: usermanual/sd
-html_location: docs/sd/umn
-link: /status-dashboard/umn/
-pdf_name: sd-umn
-rst_location: umn/source
-service_type: sd
-title: User Guide
-type: umn

otc_metadata/data/services/sd.yaml

@@ -1,5 +1,5 @@
 ---
-environment: hidden
+environment: internal
 repositories:
 - environment: internal
   repo: docs/status-dashboard