Feature Request: Adding Search Analytics

Benefits in using GitHub Enterprise don't just span code and collaboration, but also discoverability of related or interesting projects. One way to perform discovery is via the usage of the [Search](https://help.github.com/en/articles/about-searching-on-github) bar. This feature request is to potentially add search analytics to a Hubble view, so administrators can understand how this capability is used in their organization. An [updater script](https://github.com/Autodesk/hubble/tree/master/updater/scripts) could be added to discover search events.

Ideas include (but are not limited to):
- Number of searches per day
- Site-wide
- Repo-level
- Number of searches over a time period
- Most common search terms
- Searches where users discover content through [GitHub Connect](https://help.github.com/en/articles/about-searching-on-github#searching-across-github-enterprise-and-githubcom-simultaneously)

Start by reviewing the updater/scripts directory and determine whether GitHub Enterprise exposes the proposed search events. Define which of the listed measures—daily or period totals, repository scope, common terms, and GitHub Connect discovery—are feasible, then consider the work complete when the selected metrics are available in a Hubble view.

Written by the indexing model from the issue text.