Implement group membership add on first auth

In Crowd, it is possible to define a collection of groups a newly created user will be a member of, at a per-directory level:

http://confluence.atlassian.com/display/CROWD/Automatically+Assigning+New+Users+to+Groups

We would like to offer a similar feature in the common UI plugin, however, we do not need to provide a full-blown group picker. We can just expose a text field that allows the user to enter a comma-delimited list of group names that exist in the directory.

Along with the UI work, we'll need to be able to implement the actual logic that performs the auto group add. In Crowd, this is done by an event listener plugin. We can try drop the plugin into JIRA/Confluence and see if it will work - otherwise we will need to pull up the logic in the actual directory implementation.

The auto-group-add functionality only needs to be exposed to the UI on:

• Delegated LDAP with auto user add (not when auto user add is disabled)
• Read-write and read-only with local groups (not with read-only)