CLI: Config file checker / wizard

[fallwith]

It'd be neat to have a CLI tool focused on the newrelic.yml config file. It could validate existing config files for syntax, and possibly provide a wizard style interface for generating/updating a config file. For example, it'd be neat if we could ask about cloud providers and automatically disable-in-config the checks for unwanted providers; taking startup time from 3s to 1s for cloud provider based deployments, and 3s to 0s for others.

[workato-integration]

https://issues.newrelic.com/browse/NR-159402

[kford-newrelic]

Would want to be informed about nrdiag and whether this could tie in