Pull role mapping configuration from Atlas

Now that we (will) have implemented #93, we can pull role mappings into the app as well. However, I think we should reconfigure how role mapping testing is done. Namely, we should do a test to see if *any* configured groups in Atlas match the groups sent in the SAML response, and display those in the report. Error state would be if no groups overlap. We can also make the groups in the list selectable as required groups, so the test will fail if not all groups are included in the SAML response.