Tight coupling with djangoldp_account

djangoldp_account implements some of the resource server endpoints, which oidc_provider depends on

Tasks (WIP):

• the OP should perform the redirect. In our case this is performed by djangoldp_account (the RS)
• DjangoLDP-Account implements a WebFinger endpoint on the user model which discovers the issuer for the account. Since this is part of the OIDC Discovery specification I think it belongs in the OP. Reading the code it looks like it was designed to be in the OP, but was taken out because it extends a webfinger mechanism defined in DjangoLDP, but I can't be sure. One thing I find really confusing about this is that django-oidc-provider says that it implements OpenID discovery, but doesn't seem to include a webfinger endpoint at all. Needs investigation