New backoffice: Change management API base path (#13232)

* Change management api base path to  /umbraco/management/api/

* Update OpenApi schema

* Fixing some more paths

Co-authored-by: Elitsa Marinovska <elm@umbraco.dk>

src/Umbraco.New.Cms.Web.Common/Routing/VersionedApiBackOfficeRouteAttribute.cs

@@ -3,7 +3,7 @@
 public class VersionedApiBackOfficeRouteAttribute : BackOfficeRouteAttribute
 {
     public VersionedApiBackOfficeRouteAttribute(string template)
-        : base($"api/v{{version:apiVersion}}/{template.TrimStart('/')}")
+        : base($"management/api/v{{version:apiVersion}}/{template.TrimStart('/')}")
     {
     }
 }