filter out 404 error traces

They add very little value and clutter the production logs when bots scan.
respond with 404 and 500 when rendering custom error pages

includes test
update debugger to work with latest ruby
use ApiController#anonymous_access_allowed?

There are some places where we only want to require login unless you can use EIP anonymously. So far we had an anonymous_certs_allowed? method in all these controllers. Now it's replaced with ApiController#anonymous_access_allowed?. The naming better reflects that there might be other services that allow anonymous use at some point.

This also fixed a typo name -> @filename that broke the ConfigsController.
features for anonymous use and service endpoint

Also moved the location of the config files into a configuration setting.
update debugger to work with latest ruby
added destroy user to api
Merge branch 'feature/error-tweaks' of https://github.com/azul/leap_web into develop
Merge branch 'test/feature-for-service-endpoint' of https://github.com/azul/leap_web into develop