Implement OIDC token refresh/offline userinfo endpoint

[baszoetekouw]

After the regular OIDC flowin the demo RP, do a token refresh and rerequest the userinfo and dump it next to the original userinfo. That way, we can compare if the data is the same.

[logan-life]

closing as this is in Done

[baszoetekouw]

@logan-life are you sure this has been implemented? I don't see it at https://demo-sp.sram.surf.nl/rp/prd

[logan-life]

@mrvanes to add the branch or commit hash to this ticket for the impl

[mrvanes]

The feature was (only) implemented for CI, not the test RP yet.