Rename Instance Statistics to Usage Trends

Problem

Instance Statistics (https://docs.gitlab.com/ee/user/admin_area/analytics/instance_statistics.html) is a feature intended to show high-level usage statistics about GitLab activity.

This question is equally relevant to GitLab.com users and self-managed deployments, but the term "Instance Statistics" is inherently only relevant to self-managed. Although we have plans to resolve this, GitLab.com customers will never have instance-level access (they'll have expanded control over groups they manage).

Proposal

Rename "Instance Statistics" to "Usage Trends" in the UI.

Out of scope

Renaming in the underlying code will be handled under #285438 (closed).

Related links

• See "Naming something Instance Statistics" in the Product Scaling Agenda.

cc @ljlane @npost @ebrinkman