Enhance quality gate to fail when a new provider is not configured

[wagoodman]

When adding a new provider you need to remember to add a new configuration in the tests section of https://github.com/anchore/vunnel/blob/main/tests/quality/config.yaml . This is problematic since you could have a passing QG that is unaware of the new provider (thus nothing was tested).

It would be more ideal if the QG could look at src/vunnel/providers and understand if there is a provider that is missing a config.yaml entry and fail when that case is detected.