feat: add metadata via header annotations in rego

[Mattes83]

Hi there,

I am trying to implement a solution for #322.

What do you think?

Best regards

[jpreese]

This looks like a strong start to me, @Mattes83. Would you mind adding a test for the generation of annotations?

Easiest may be adding this new metadata to the test folder but you could also add it to one the examples.

Just as long as we're verifying that the comment header in the Rego produces the expected YAML.

[jpreese]

@Mattes83 this has been released in v0.24.0