MAINT: Update Google Analytics

[mmcky]

It seems there is a change to Google Analytics coming in July this year

On 1 July 2023, this property will stop processing data. Starting in March 2023, for continued website measurement, you should create a new Google Analytics 4 (GA4) property, or one will be created for you based on your original property and reusing existing site tags.

cc: @DrDrij

[mmcky]

@AakashGfude @DrDrij

The new jupyter-book==0.15.1 required we move the analytics in _config.yml to its own section rather than be in the theme section within sphinx config.

@AakashGfude does quantecon-book-theme work with this new location in _config.yml

All our sites have no analytics at the moment, and I am working with @DrDrij to update to G4 codes at the same time