Add new Drafts Tab to Merge-Request View
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This is kinda small feature Request and should be simple to implement I guess,
We currently have a lot of conception work on our projects and use the DRAFT functionality of Merge-Requests, and we would love to have them separated from the Open Tab in the Merge-Request Window. (see below)
If the Open Tab should stay like the overall Open Merge-Requests View, then there would be some sort of Ready for Review Tab nice to see open and reviewable Merge-Requests.

In the same effect we would love to have some sort of more visibility for approved MR's so we could easily adapt a simpler workflow, when we have like 20-30 MR's
### Release notes
Clean organization of DRAFT MRs with new Tab Draft in Merge-Request View
### Problem to solve
### Proposal
Implement a new Tab to the Merge-Request View for Drafts to separate them from the Open View. (Or use some sort of Ready for Review as clarification for reviewable Merge-Requests)
### Intended users
Developer, Maintainer
* [Parker (Product Manager)](https://about.gitlab.com/handbook/product/personas/#parker-product-manager)
* [Delaney (Development Team Lead)](https://about.gitlab.com/handbook/product/personas/#delaney-development-team-lead)
* [Presley (Product Designer)](https://about.gitlab.com/handbook/product/personas/#presley-product-designer)
* [Sasha (Software Developer)](https://about.gitlab.com/handbook/product/personas/#sasha-software-developer)
### Feature Usage Metrics
### Does this feature require an audit event?
No
issue