Feature: Option to have WIPs in a separate tab

Problem to solve

I've seen and worked with many projects with lots of WIP merge requests (this one is an example). What I realized (and other devs that work with me too) is that, when you have a considerable amount of open WIPs, it clutters the open MRs list and makes it difficult to focus on the ones that are ready to be reviewed and do not expect any big changes. Also, when trying to measure visually the bottleneck of open MRs as work that is ready but not making it to production, having the WIPs in the same list is just noise and not a good thing.

Proposal

I think it would be good to have the possibility to have the WIPs in a separate tab. In order to not change the behavior that much and for people that do not see that as a problem, one could just opt-in for the tab separation, per project.

Examples:

We could have a link on the right side of the tabs in order to opt-in for that:

And when clicked, all WIPs would be in their own tab:

/label ~"feature proposal"