Enable Google integration when running OpenRefine behind a proxy

[wetneb]

Posted by @matiasgarciaisaia at OpenRefine/OpenRefine#3627 (comment):

If OpenRefine runs behind an HTTPs reverse proxy, Jetty 6 doesn't set the correct client's schema on the HttpServletRequest object, causing the generated redirect_uri for OAuth to always be plain HTTP - which Google forbids for external OAuth applications.

Although OpenRefine is not designed to be hosted online, we are aware of a few places where this is done, and therefore those uses could benefit from making the Google integration usable in this context.

@matiasgarciaisaia proposed a PR which fixes this for Jetty 6: OpenRefine/OpenRefine#3627.

In the meantime we upgraded to Jetty 9. Therefore a new solution for this version of Jetty could be found.