Remove GA analytics.js add gtag.js script

[Gnito]

Google analytics script changed

Universal Analytics (analytics.js + measurement id starting with "UA" prefix) is sunsetting in 2023.

This PR removes UA integration and adds Google Analytics 4 (GA4) instead:
gtag.js script + it expects measurement id starting with "G-" prefix.

In addition, the trackPageView method of analytics handlers now gets 2 parameters:

• The first parameter still holds the canonicalPath of the (next) page.
• The second parameter is a new one: it contains information about the previous path.
  This is needed for GA4, which by default always sends page_view event on page load, but in-app navigation after that should be sent manually. If the previous path is non-existent, this manual call should be omitted.

There are some notable issues related to GA4

Enhanced measurements

By default, Enhanced measurements are on. This means that gtag.js adds its own code to all kinds of event sources like links <a>. This seems to be slow code and most likely breaks in-app navigation.

Our links look like normal links but React Router adds its own click event listeners to them and bypasses the default link behavior that causes full page load. With the code attached by GA4, the event handling is too slow and the code probably doesn't prevent the default behavior (which should be prevented - otherwise, the event gets bubbled up to default behavior).

It's probably best to turn Enhanced measurements off.

https://support.google.com/analytics/answer/9216061

If that's not an option, then you should at least turn

• Outbound clicks events off and
• Page changes based on browser history events off.

Page title is sent to GA4

This is problematic because FTW's the routing first changes the location and then on a new location it renders the page and URL parameters (path params, search params, hash) are taken into account during rendering.

So, history.pushState happens before the page title (<title>) is rendered. Therefore, we have used setTimeout to give the page 300 milliseconds to render something after the 'LOCATION_CHANGED' action.