Add new analytics nav section
With GitLab 12.2, analytics-related functionality is moving to its own space. This has been reflected in the docs.
This MR reflects it in the navigation.
Preview: http://add-analytics-section.178.62.207.141.xip.io/ce/user/analytics/, http://add-analytics-section.178.62.207.141.xip.io/ce/user/analytics/cycle_analytics.html.
Edited by Evan Read