Normalise gene (count) data properly for MOFA

[joewandy]

See https://hbctraining.github.io/DGE_workshop/lessons/02_DGE_count_normalization.html

Seems like deseq can do it? https://www.biostars.org/p/317023/

Also see https://biofam.github.io/MOFA2/faq.html for MOFA @KeqingWangg