Add bayesAB function for Bayesian A/B testing

Why it matters

This feature enables users to apply Bayesian statistical methods to A/B testing scenarios in their data analysis, providing probabilistic insights and decision-making support that go beyond traditional frequentist approaches.

How to use it

Use the bayesAB function in your SQL queries to analyze A/B test results. It can be called by passing the relevant parameters representing experiment data to compute Bayesian posterior probabilities.