Added AI Summary, Pre-Test Calculator & PostHog

1. Added AI Summary, your personal analyst.
2. Pre-Test Calculator using BigQuery data.
3. Added support for PostHog.
4. All scheduled queries for all tools are changed.
5. Adjusted some Apps Script due to changes mentioned above.
6. Changes to Settings & Experiments sheets. This is done using Apps Script, so no manual work.

How to upgrade:

• https://github.com/Knowit-Experience-MarTech/bigquery-ab-analyzer/tree/main/03-Releases/v2.0

Initial release

Initial release of the BigQuery A/B Analyzer framework.