Migrate from Universal Analytics to Google Analytics 4

[krivard]

Delphi currently uses a Universal Analytics property to track our site usage. Google will stop processing hits in Universal Analytics on July 1, 2023. Before that date, we should follow their instructions to migrate to GA4.

Roughly, this includes:

[sgratzl]

first requires to use the new token in https://github.com/cmu-delphi/www-main/blob/563b25bd78ea70a322d98a7ae50aaf5e2bb69625/config.toml#L5

see also https://gohugo.io/templates/internal/.

then we can see how much we have to change: https://github.com/cmu-delphi/www-covidcast/blob/dev/src/stores/ga.ts