[W.I.P.] Ubi integration

[RasonJ]

Description

Integrates User Behavior Insights logging in the documentation website.

Issues Resolved

Tracks individual user interactions with the documentation website, so that we can use analytics to optimize the site utility for other users.

Events tracked:

• all gtags are copied into ubi events index
• search terms and results
• item_clicked
• page_exit
• dwell time
• 404 redirect

Checklist

• [ x] By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and subject to the Developers Certificate of Origin. For more information on following Developer Certificate of Origin and signing off your commits, please check here.