Handle additional assays: ATAC-seq, then CODEX

[mruffalo]

No description provided.

[mruffalo]

The presentation of each additional assay type will differ from the RNA-seq presentation -- we won't be doing as much analysis of each consolidated result for some other assays, so there may not be as much to show.

We'll almost definitely want a base_detail.html template, then rna_detail.html extending that in a way that's equivalent to the current one, and atac_detail.html with a bit less information. UI elements like the dataset list should be reused when possible (defined in the parent template).

[mruffalo]

Also common: number of cells/nuclei.