Create EE::Auth::ProvisionedUsersFinder, which returns
a list of users who are provisioned by a SCIM identity
or managed by a SAML group. ProvisionedUsersFinder is then
exposed by a new API endpoint,
GET /groups/:provisioning_group_id/provisioned_users.
Group maintainers can use this endpoint to list
provisioned users for a given group.

Changelog: added
EE: true