Enterprise home: Track event analytics

Created by: limitedmage

We want to track event analytics for the new enterprise home. List of events are in the product document here: https://docs.google.com/document/d/1mkBQS6us1lD7IuZmbHq_N9DZqZ0kfqd30gaikOp4Re4/edit#heading=h.x8wbn3l5z16

• Percentage of users whose Repository panels are empty
  • Add the count of recent searches, repos, etc that show up to the ViewHomePage event argument
• Use of panels as entry points into the application
  • Clicks into each section from the home panel
    • Recent searches
    • Recent files
    • Recently searched repositories
  • From the home page, what percentage of entry points come from the panels vs. others (others = search bar)