feat(dockerfile): add support for recognition of Containerfiles

[steven-deboer]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Description

Although Containerfiles are using the same syntax, checkov could not recognize those files for checking. This update adds recognition of Containerfiles additional to Dockerfiles for the same checks.

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that prove my feature, policy, or fix is effective and works
• [ ] New and existing tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules

[stale[bot]]

Thanks for contributing to Checkov! We've automatically marked this issue as stale to keep our issues list tidy, because it has not had any activity for 6 months. It will be closed in 14 days if no further activity occurs. Commenting on this issue will remove the stale tag. If you want to talk through the issue or help us understand the priority and context, feel free to add a comment or join us in the Checkov slack channel at codifiedsecurity.slack.com Thanks!

[Saarett]

Hi @steven-deboer , please let me know if you're planning on completing this change. Thanks

[pazbechor]

@steven-deboer Closing this one as out-of-data & inactivity :) Open it in the future if it's still relevant!