SimpleSAMLphp

@sherakama This should have no effect on existing Sites installs; simply adding simpleSAMLphp as an option (preparing for moving to cloud).

Please do not delete the simplesamlphp branch after merge.
Hrm. Not sure if I agree on this, actually. Most of the functionality of stanford_sites_helper is useful outside of sites. If anything, we should wrap the AFS quota check in the stanford_sites_hosted() check. 

And by "we", I mean our future selves.