DEVP-3540 feed issue relationships

[MickStanciu]

Summary

add a new feed for issue relationships

Problem description

Pros/cons of approach implemented

Checklist

• Is this PR a reasonable size?

• List deployment sequence with all relevant PRs.
  • ...

• For breaking changes: I have confirmed that other repos are not affected, or I have planned a deployment sequence to address any impact.

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Code Review Guidelines for Reviewers

• Try to review in a timely manner. Opinions/nitpicks should not be blockers. Pair on a call for non-trivial feedback.
• Overall design and approach should follow established patterns. Don't try to make the PR perfect.
• Try to identify edge cases, race conditions, over-engineering, lack of test coverage and complexity.
• If you don't feel qualified to review the code, pass it on to someone who is.