* Extract Normal and Standard Normal Distributions from the Statistical Class
* Extract ZTest from the Statistical Class, and move it to the Standard Normal Distribution class
Additional unit tests for NORMINV()
* Extract LogNormal distribution functions from Statistical
* `GAUSS()` and `GAMMA()`, `NORM.S.DIST()`, `LOGNORM.DIST()` and `F.DIST()` function implementations, and further unit tests for a number of the statistical functions
Co-authored-by: Adrien Crivelli <adrien.crivelli@gmail.com>