add checkov to the ci pipeline

What does this MR do?

Following a bit the Everything Starts with a Merge Request approach here.

This adds checkov to the CI pipeline. It is set for soft-fail, meaning that it wont block the pipeline, it will just generate a report for visibility. We can then iterate on it 😃

If you don't feel like this is the right time or approach to add this, feel free to discard the MR and we can discuss a better approach later.

Related issues

Closes #306 (closed) #91

Author's checklist

When ready for review, the Author applies the workflowready for review label and mention @gl-quality/get-maintainers:

• Merge request:
  • Corresponding Issue raised and reviewed by the GET maintainers team.
  • Merge Request Title and Description are up to date, accurate, and descriptive
  • MR targeting the appropriate branch
  • MR has a green pipeline
• Code:
  • Check the area changed works as expected. Consider testing it in different environment sizes (1k,3k,10k,etc.).
  • Documentation created/updated in the same MR.
  • If this MR adds an optional configuration - check that all permutations continue to work.
  • For Terraform changes: setup a previous version environment, then run a terraform plan with your new changes and ensure nothing will be destroyed. If anything will be destroyed and this can't be avoided please add a comment to the current MR.
• Create any follow-up issue(s) to support the new feature across other supported cloud providers or advanced configurations. Create 1 issue for each provider/configuration. Contact the Quality Enablement team if unsure.