Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1463776

Description of problem:
[RFE] - When you go to configure ldap authentication, if you don't have the right External user group "Name", it will fail when you try to submit it. Since you've already configured everything at /auth_source_ldaps, the valid possibilities should be listed to you on the /usergroups#external page.

1. Proposed title of this feature request
[RFE] - You should see the possible "Name" for External user group

2. What is the nature and description of the request?
When you go to configure external authentication, you need to set the name of the ldap group:
https://access.redhat.com/solutions/1231433
"On the External groups tab, click the Add external user group button to open a new form. In the Name field, enter the exact name of the LDAP group (usually the common name/CN) and select the server from the dropdown list of LDAP authentication sources. Click the Submit button to save changes. In this instance I have created a AD group called "sat6" and added users in to it."

You've already entered all the authentication credentials when you created the ldap authentication source, so rather than manually typing in the name at /usergroups#external.

3. Why does the customer need this? (List the business requirements here)
This will make it easier and less error prone when you are setting up ldap auth.

4. How would the customer like to achieve this? (List the functional requirements here)
In the webui, Name should be a dropdown like Auth source is.

5. For each functional requirement listed, specify how Red Hat and the customer can test to confirm the requirement is successfully implemented.
If when you're setting up External groups for a user group you can drop down a list for Name, that's what we need.