Change default extraction method for factor analysis to be based on factors (instead of principal components)

[patc3]

This also clarifies the labels for the parallel analysis, which were adjusted recently for the principal components analysis but not the factor analysis.

[juliuspfadt]

Thank you @patc3 for the PR. I agree that it is inconsistent to have EFA and then run the parallel analysis by default based on PCs, however I think we had a reason for this, which is that it performs better, and I think it was based on this paper: http://dx.doi.org/10.1037/met0000200. we had a somewhat related discussion about these types of inconsistencies here jasp-stats/jasp-issues#2418. In general, I am planning to split the analyses into one to determine the number of factors/components and one the runs EFA or PCA. I think we would then not run into these types of inconsistencies. But I dont know when I will get around to it.
Anyways, I am not feeling very strongly about the default parallel analysis method.