Shibboleth2 is EOL #8405
Description
The Shibboleth guide page links to the Shibboleth2 wiki page but Shibboleth2 is EOL. We should link to the Shibboleth3 page instead.
Further, the Shibboleth project now provides a webform to generate an appropriate Shibboleth repo, so we might safely replace most of the "Enable Shibboleth Yum Repo" with this form.
Pull request forthcoming.