Redirect for moved issues and duplicate issues

Problem

• Right now when you “move” an issue to another project, it is closed and a new one is created in the target project.
• This is similar for marking issues as duplicates.
• So when users go to the previous/duplicate issues, they have to scroll to the bottom of the system notes and click to access the new issue.

Proposal

• Have automatic redirects so that the previous/duplicate issue links go to the new one.
• You should still be able to access the old issues explicitly. Perhaps you need to have some URL params that tells GitLab not to redirect. And these could appear in the system notes of the issue you are redirected to.
• We also have to handle the situation of how to render the links of the duplicate / moved issues.