MR Analytics: Throughput chart MVC

Problem to solve

Many devops organizations rely on "throughput" as a measure of productivity. GitLab defines throughput as the number of MRs merged in a period of time (specifically "throughput per month-long milestone").

See the discovery issue for more details.

Proposal

Add a "Throughput" chart to the group-level "Merge Requests Analytics" page. This shows "The number of merge requests merged by month." (Regardless of target branch.) In this iteration it shows the past 12 months.

MR Analytics should be available in GitLab Starter.

This MVC feature is at the project level.

Out of scope

• 2nd line for average
• Filters
• Merge Request list/table below the chart

Implementation

• backend #229047 (closed)
• frontend #229048 (closed)

See the discovery issue for more details.