Issue boards UI
What does this MR do?
UI for issue boards.
Are there points in the code the reviewer needs to double check?
Why was this MR needed?
What are the relevant issue numbers?
- Issue: #17907 (closed)
- Backend MR: !5548 (merged)
- Frontend MR: !5554 (merged)
- Documentation !5713 (merged)
Screenshots (if relevant)
