docs: updating the --ignore-policy flag and policy docs

[AnaisUrlichs]

Description

I have done the following

• updated the documentation on misconfiguration scanning to detail the "different types of policies" that we have and that users can pass into the misconfiguration scan. This is based on my conversation today with Itay. Eventually, we might want to rename the --policy that is passed into the misconfiguration scan into --check and similar across the documentation and the CLI (discussed in more detail in this discussion: Ignoring stuff #3620 )
• I have provided further details to the --ignore-policy flag so people better understand where this information is coming from and how to apply it. As this issue describes, the docs was incomplete --ignore-policy unavailable in config target #3490 -- In this issue, there are still some updates mentioned that have to be made in the CLI for --ignore-policy (namely: exceptions are not displayed correctly and --ignore-policy does not work for trivy config command directly at the moment)

Related issues

• It might be possible to close this issue Improve documentation of ignore-policy #3486
• Also, this issue might be ok to close since multiple people mention multiple issues in the docs Support Inline Filtering #2961

[AnaisUrlichs]

I also ran docs:generate so some changes have been made to the reference docs -- wasn't sure if I should leave that or make a separate PR for those

[itaysk]

I think rendering is still broken, can you please fix before I re-review?

[AnaisUrlichs]

Will check, it displayed it correctly for me yesterday

[AnaisUrlichs]

It does not work when you preview the markdown but it renders correctly when running the docs locally:

Locally

Localhost

[AnaisUrlichs]

@itaysk thoughts on turning this into a tutorial instead?

[itaysk]

This PR includes two things:

1. fix an error in the docs incorrectly documenting the input to the rego rule
2. better explaining why and how to use ignoring with rego rule

I think it's a good idea to take the explanatory content you added here into a tutorial, but we still need to fix the documentation error:

The structure of each vulnerability input is the same as for the Trivy JSON output.

[itaysk]

This is the issue that prompted this PR, can you please add it to the PR description? #3486.

[github-actions]

This PR is stale because it has been labeled with inactivity.