Add Container Definition for COBOL

[elswork]

Add COBOL devcontainer to compile and run COBOL
Create a new pull request following @bamurtaugh suggestions in an earlier Pull Request #1280

[bamurtaugh]

Thanks for making the updates @elswork!

Also as a note, we are looking into how we can enable the community to more easily share definitions and features like those in this repository. There are additional details in this issue: #1291.

[bamurtaugh]

Thanks again for opening this PR!

As I mentioned earlier, our team has been actively focused on an updated plan for community contributions and this repo moving forward, which we've now outlined in this issue: #1589. This includes moving to a couple new repos for images (https://github.com/devcontainers/images) and Features (https://github.com/devcontainers/features).

We anticipate to have a similar repo and distribution process for templates/definitions. We'll keep everyone updated (likely via another issue in this repo or comment on #1589) when our new templates repo is available and the process is defined.

Please let me know if you have any questions, thank you!