we have one global metrics variable `metrics = GDSMetrics()`, and we
then call `metrics.init_app` from within the flask application set up.
The v2/test_errors.py app_for_test fixture calls create_app, would call
metrics.init_app multiple times for the same metrics instance. This
causes errors, so change the fixture to session level so it only calls
once per test run.
Handle werkzeug http errors separately. Also, improve the generic
`Exception` handler to be more flexible when exceptions don't look
like http errors.
note: because they're 405s the route isn't matched, so the v2 error
handlers don't trip properly. this might be an issue because the
internal endpoints expect a different return format. Might have to
think about how to handle this.
Since the response has changed I have created new endpoints so that the deployments for Admin are more managable.
Removed print statements from some tests.
