Introduce `append_related_issues` function and `IssueRelated` enum to manage related issue linking. Update Gitea action to utilize the new functionality for appending related issues in work package content. Add corresponding tests.
Introduce `append_related_issues` function and `IssueRelated` enum to manage related issue linking. Update Gitea action to utilize the new functionality for appending related issues in work package content. Add corresponding tests.