Add scenario lists to scenarios interface

This commit wires up scenarios to the scenarios
interface. It uses the scenario API to query
for a list of scenarios.

A few notes about this commit
 - styling for colleague's scenarios still needs
   to be done
 - pagination was easiest/fastest if all the scenarios
   are pulled down initially then grouped; this limits
   the number of requests made to the server and not likely
   to cause a problem with the size of the request since
   the scenario metadata is small anyways.
Gunicorn doesn't seem to care whether its true or false for displaying stack traces, but regardless you're probably right