Optionally pass HTTP request to oauth SPI

[gbrail]

The Apigee OAuth SPI supports a mode in which it will automatically update analytics inside the Apigee platform, but it needs the original HTTP "request" object passed to it in order to do that.

I don't believe that volos-oauth-common does this today, and we'll need to add it if we want to get good analytics on the data passing through the proxy.