os.environ is an `environ` object, not a dict. by only interacting with
it through builtin functions we can ensure it remains properly
accessible to third party libraries which might interact with it in
different ways.
See https://github.com/alphagov/notifications-api/commit/d2441466 for
more detail
We're no longer using user-provided services for application secrets
so we can remove the cloudfoundry_config code responsible for parsing
VCAP_SERVICES.
previously in run_app_paas.sh, we captured stdout from the app and
piped that into the log file. However, this came up with a bunch of
problems, mainly that exceptions with stack traces often weren't
formatted properly, and kibana could not parse them
instead, with the updated utils library, we can use that to log json
straight to the appropriate directory directly.
pass in the base URL - if not set in the environment this is set to
localhost, but on paas we can pull this out of vcap_services so that
letters render properly on paas
