Provide guidance on the Google Analytics upgrade

Universal Analytics standard properties will stop processing data on July 1, 2023. Google recommends that w switch to Google Analytics 4 now.

If we don't setup a GA4 property with basic settings, starting in March, google will configure one with a few basic settings consistent with the existing Universal Analytics property; this includes certain conversion events, Google Ads links, and existing website tags.

For websites tagged with gtag.js or analytics.js (including through tag management systems like Google Tag Manager), Google will create a connected site tag that will reuse existing tags when possible to send traffic to the new GA4 property. However, it's possible for users to opt out.

We need to research what all of this means and provide some guidance to our projects.

This was raised on #568 (comment 1077144) by @aberezovsky.