Implement ten Berge factor scores

[jbiggsets]

Is your feature request related to a problem? Please describe. Nope!

Describe the solution you'd like There are multiple ways to calculate factor scores. Currently, factor_analyzer implements the regression-based Thurstone method; however, the the Berge method does a better job of preserving the original correlations.

Describe alternatives you've considered Alternative is not to implement this.

Additional context Here is a preliminary implemenetation:

https://stackoverflow.com/questions/67856186/correct-way-to-calculate-correlations-between-factors/67895893#67895893