Add user management section (#809)

docs/user_management/user_groups.md

@@ -0,0 +1,14 @@
+---
+title: User Groups
+---
+
+:::important Enterprise Feature
+User Groups are available under the ClearML Enterprise plan
+:::
+
+Administrators can define user groups, which can be used for access privilege management. User groups facilitate easy 
+configuration and access control administration by allowing administrators to assign administrator vaults and access 
+rules at the group level rather than for each user and/or [service account](../webapp/webapp_profile.md#service-accounts) 
+individually. Administrators have the flexibility to create user groups, and add or remove members as needed.
+
+For more information see [User Groups](../webapp/webapp_profile.md#user-groups)