How to add percent progress metric to issue to track progress of the issue?

Hi,

I am using latest community version of Gitlab and it is self-hosted.

Want to add more attributes to Issues like Work Done in %, new issue status like “Deferred”, “Can not reproduce” etc.

Also, We follow Sprints. When I close Milestone, all the open issues should move to Backlog. How can I configure this too?

Regards,
Suraj