Switch size factor analysis to pyDESeq2

[abearab]

Here there is a size factor calculation in R which can be painful (i.e. setting up stable environment, etc.) ! I would use pyDESeq2 since it's now a well maintained python tool.

from pydeseq2 import preprocessing
_, size_factors = preprocessing.deseq2_norm(adata.X)

[Zethson]

Hey,

generally in favor of this. It will happen at some point. PRs are generally welcome!

[abearab]

Cool!