While we might never be able to have 100% of our code strict, we can at
the very least do it for all of our tests. This ensures that our tests
are using our API with the types as intended by the test author, and not
silently be cast to what our API requires.
* 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>