DS-2048 : Allow more flexibilty in assigning DSpace groups to Shibboleth affiliations

Redone the way DSpace groups are assigned to Shibboleth affiliations.
This PR removes the authentication-shibboleth config options ignore-scope ignore-value. 
This log info is pretty useful in tracking down access-rights issues. I know it looks like debugging, but you never know when these issue might crop up in production, it's useful information to have, and I'd hate to require a recompile/deploy/restart just to enable it.