[DOC] - Include examples for general config files for all cloud providers

[viniciusdc]

Preliminary Checks

• This issue is not a question, feature request, RFC, or anything other than a bug report. Please post those things in GitHub Discussions: https://github.com/nebari-dev/nebari/discussions

Summary

Right now, we only have a full example for GCP on our docs, and it might be useful as a reference point for our users to have such information present.
completehelpful

Steps to Resolve this Issue

1. Check if the config reference currently present in our docs is up to date;
2. Add remaining providers;
3. Explore ways to keep config up to date -- possibly dependent on Pydantic PR