Remove deprecated Elasticsearch analytics plugin and analytics logic

What does this MR do and why?

WHAT

This MR removes behavioral analytics logic + plugin due to [deprecation](There are some docs here, but they seem outdated since they don't mention the deprecation: https://www.elastic.co/guide/en/search-ui/current/api-core-plugins-analytics-plugin.html).

WHY

Right now Google Analytics is already tracking way more information and Elasticsearch analytics is limited only to the admins (so anyone who doesn't have admin access can't see the dashboard at all - not useful 😞 )

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Configure a local GitLab Docs environment.
2. Check out this branch.
3. Make sure you can do the following,

• Search is searching + giving results.
• From search results page, you can click on the URLs (i.e. normal click or right click to open in new window/tab) and it will take you to that content page.
  • NOTE: This behavior had to be specially implemented previously because we had to add tracking to clicks. In this MR, this logic is deleted but links should work as normal!
• No console errors!

Merge request acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this merge request.

Closes #311 (closed)