Consider methods to annotate 'adjacent normal' tissue

[jjacobson95]

The crcorganoid data has some samples that are not cancer samples, but are instead healthy tissue from the same organoid.

I am adding this issue so this isn't forgotten. Eventually it might be nice to have a separate model type or other way to denote this.

[sgosline]

Probably related to #393 and #392 , but i will investigate.

[alexandriai168]

in this dataset, the adjacent normal samples have "Colorectal Carcinoma" as their cancer type. They are denoted in the "other_id" column as something like "P8-Normal-Organoid"

[sgosline]

These should just be 'Normal' as a cancer type.