For the 3-legged OAuth exercise, don't require the user to import the OAuth proxy

[DinoChiesa]

For the 2-legged OAuth exercise, we do not require users to import an OAuth CC proxy. But for the 3-legged exercise, we require users to import the proxy that implements the Authorization Code grant. This seems non-optimal.

I think for the devjam, we should bundle our own oauth dispensary proxies, one for CC, one for password, one for AC... And there should be a requirement for devjam setup that the proctor import those proxies into the environment prior to the lab work starting.

Every student can depend on the same OAuth dispensaries, whether CC AC PWD, or whatever.

Also, I suggest that for 3-legged, we get away from the fake user login thing that we implemented with RaiseFault and static HTML. That code was delivered in 2014. We can now embed nodejs into proxies, so we should use that to support the user-login and consent experience.

I have a working example of a suitable proxy. See attached.
apiproxy-oauth-3legged-20170404-122229.zip