Move the how to to the Admin guide section

Author: ale-rt

docs/backend/users-groups/emergency-user.md renamed to docs/admin-guide/add-emergency-user.md

@@ -30,6 +30,7 @@ install-pip
 
 run-plone
 add-site
+add-emergency-user
 configure-zope
 add-ons
 export-import

docs/admin-guide/index.md

@@ -0,0 +1,13 @@
+---
+myst:
+  html_meta:
+    "description": ""
+    "property=og:description": ""
+    "property=og:title": ""
+    "keywords": ""
+---
+
+(backend-users-groups-label)=
+
+# Users and Groups
+