Draft: Redesign Merge Requests top menu

What does this MR do and why?

Adds new item in Merge Requests top menu with link to list of requested reviews without user's approval.

In our company we don't remove ourselves from reviewers list after approving MR, so requested review is counted as long as MR is opened. Unfortunately code review process may be long and with requirement for 2 approvals it leads to situations when first reviewer already gave approval and is waiting for other reviewer while having this approved MR counted in menu. This new menu item will help to keep track of MRs that still requires approval.

Draft info

Since it's second time I work with Gitlab's code and processes I just don't know if everything what I've done is correct. I have problems with running specs locally (FAILED to connect to gitaly) so I don't know if they'll pass. Also I have some doubts which I will add later as code discussions.

Screenshots or screen recordings

Before:

After:

How to set up and validate locally

1. Create MR as user1
2. Set user2 as reviewer for that MR
3. As user2 look at top menu, you should have MR in both counters (All / Awaiting approval)
4. As user2 approve MR
5. "Awaiting approval" should have decreased (ℹ but it does not → cache problem)

MR acceptance checklist

• I have evaluated the MR acceptance checklist for this MR.