Making instance-wide data tools more accessible

Description

Right now, there are several instance-wide tools in GitLab that can be interesting to various users, but they are only available to administrators as they are part of the admin panel.

Proposal

A new link will be added to the top bar as an icon, the same way that we display the Admin Area. The icon will be icn/charts.

When the user clicks the icon, they'll be taken to a new Instance Statistics navigation in a descriptive path like /stats. Inside, there will be two top-level navigation elements: ConvDev Index (icn/comment) and Cohorts (icn/users).

ConvDev Index	Cohorts

When the user is an admin, they will see both the Instance Statistics and Admin Area icons in the top bar next to each other.

Instance Statistics will be available for all users by default. Access can be limited from the Admin Area under the Usage statistics section.

The control will be a dropdown labeled Instance Statistics visibility with options All users and Only admins.

Links / references

added to epic &28 (closed)

changed title from Making instance-wide tools more accessible to Making instance-wide data tools more accessible

added to epic &39 (closed)

mentioned in issue #41780 (moved)

mentioned in epic &39 (closed)

@jramsay @jeremy_ can we do this in the near future?

@JobV can we now have an exception for existing instances (80% of GitLab for the next few years) and just introduce this in GitLab 11?

@jramsay, excited to discuss when we do pre-planning for GitLab 11. Might also be a good one to flag for @sarrahvesselov's if we're proposing a new element in the dropdown.

I'd also want to see if we can tackle https://gitlab.com/gitlab-org/gitlab-ee/issues/5674 (ConvDev > DevOps Score) before or at the same time.

added UX label

Thanks for the ping @jeremy_ , I added the UX label so we have visibility on this one.

changed milestone to %11.0

Explanation of @sytses comment: Turn this on by default for all instance (don't do the exception for existing instances). We wouldn't normally do this, but given that 11.0 is a major release and we make this clear in the blog post, we should take the opportunity to do so.

I'm editing the description to match.

changed the description

added backend label

Notes from discussion:

• Data is relevant to the entire instance, but should be accessible to everyone/more people.
• Option to have this data available or not

added Deliverable label

added DevOps Score label

assigned to @pedroms

Excited to see this in 11.0. I'm wondering if Instance Statistics makes more sense to be affiliated with the Activity button in the nav topbar instead of the top-right profile dropdown. When clicking on my picture, I associate that area with "options and settings that are related to me, personally", which matches every option presented (aside from Help).