Add policy message examples to the simple demo

[brandtkeller]

Is your feature request related to a problem? Please describe.

For the demo/simple/oscal-component-*.yaml - the addition of a msg in the policy coupled with opa-spec/kyverno-spec.output implementation can help provide better output messages to the assessment-results. We should highlight this behavior by default.

Let's add an addition to that validation to support more information around why the scenarios are or are not satisfied.

Describe the solution you'd like

• Given the demo/simple/oscal-component-opa.yaml has the output specified
• When lula validate is executed
• Then a message is printed into the assessment result containing information as to why the validation passed/failed.

Additional context

See the mention of output for each provider available:

1. https://github.com/defenseunicorns/lula/blob/main/docs/reference/providers/opa-provider.md
2. https://github.com/defenseunicorns/lula/blob/main/docs/reference/providers/kyverno-provider.md

Expected Deliverable

• Validation in demo/simple/oscal-component-opa.yaml contains conditional messages that indicate why the policy logic passed/failed.
• Validation in demo/simple/oscal-component-kyverno.yaml contains output to observations