Add enhancement `last-scanned-timestamps`

[SimonBaeumer]

This PR adds an enhancement to add a field LastScannedTimestamp to the CheckResult CR.

This enhancement is planned to be implemented by myself. This first iteration is to get consensus on the feature request and discuss possible implementations if necessary.

[openshift-ci[bot]]

Hi @SimonBaeumer. Thanks for your PR.

I'm waiting for a ComplianceAsCode member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: SimonBaeumer Once this PR has been reviewed and has the lgtm label, please assign mrogers950 for approval. For more information see the Kubernetes Code Review Process.

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[rhmdnd]

/ok-to-test

[xiaojiey]

/hold for test

[SimonBaeumer]

See #512

[openshift-ci[bot]]

@SimonBaeumer: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-aws-serial	fec136efd4e56b24c5a84b025997788202bc8e7a	link	true	/test e2e-aws-serial

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[Vincent056]

we have implmentation in https://github.com/ComplianceAsCode/compliance-operator/pull/591