Add an action to label/unlabel PRs with JIRA URIs

[jmtd]

Thanks for submitting your Pull Request!

Please make sure your PR meets the following requirements:

• A JIRA issue must exist in the OPENJDK project at issues.redhat.com
• Pull Request title should be prefixed with the JIRA issue: [OPENJDK-XYZ] Subject
• Pull Request contains hyperlink to the JIRA issue
• Pull Request contains description of the issue
• Pull Request does not include fixes for issues other than the main ticket
• Attached commits represent units of work and are properly formatted
• You have read and agreed to the Developer Certificate of Origin (DCO) (see CONTRIBUTING.md)
• Every commit contains Signed-off-by: Your Name <[email protected]> - use git commit -s