update documentation for google analytcis

[alexskr]

Documentation for Google Analytics V4 needs to be updated.
Specifically we need to document how to create analytics_path_to_ua_data_file

[mdorf]

I updated the documentation on generating the Universal Analytics data (requires e8fa020) and setting up configuration for Google Analytics Data (GA4). That commit also fixes an error that happens if the Universal Analytics data file does not exist or is empty.

@alexskr still needs to update the portion of the documentation that details how to obtain the GA4 property ID as well as the myontoportal_analytics_key.json file to authenticate with Google servers. The GA4 authentication no longer uses the p12 key file.