Enabling lightweight and federated accounts access in CERNBox

<!--HTML-->Access to CERNBox via social account providers and external emails provides a highly scalable and traceable mechanism to allow sharing of data and knowledge with people external to CERN, and encourage collaboration across boundaries and institutes. In this talk, we'll talk about how we adapted our service to accommodate such accounts with restricted scopes and describe the developments that were needed to our EOS storage connector to facilitate sharing of resources with them.