Integrate with IdentityServer to obtain Auth Tokens

[jrhender]

An initial implementation of the Auth server is up at https://asktoniauthentication.azurewebsites.net/
We need to integrate it with the client. I think the first step is to implement a flow so that the client can request a token and handle a response when it comes back. A general approach is here: https://identityserver4.readthedocs.io/en/release/quickstarts/7_javascript_client.html
The heavy lifting can be done by https://www.npmjs.com/package/oidc-client
I think we'll also need to modify the auth server to add/allow the client

[RedTn]

@jrhender Is there some endpoint that I can test with a token? The staging and prod api still seem to not need tokens.
Ideally, this could be pushed into staging, but after the recommendations endpoint has been pushed to prod.