fix: use SecretBytes type for cert values to prevent accidental printing

[4141done]

Proposed changes

We save the values of the provided certs that we retrieve from Kubernetes secrets in the Certificates attribute on the Certificates struct.

This is sensitive information that we want to make sure stays out of the logs and any stack traces. A common approach to this is to create a type definition for sensitive values that implements Stringer and JSON interfaces and cast the sensitive data to that value.

Help

I'm very new to Go. I may have made some non-idiomatic choices or failed to use features which could have improved this.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md and CHANGELOG.md)

[ciroque]

One minor nit, otherwise this is a nice clean addition to the code

[ciroque]

@4141done do you need anything from me to merge this?

[4141done]

@4141done do you need anything from me to merge this?

If you have time would you be able to run a test pass on it? That's what I keep not having time to go through. Otherwise I think we are good.

[ciroque]

Confirmed integration test works.