Enhancement: Color the UMAP using cluster information found in categories

[veroniquevoisin]

In order to make a link between the UMAP (or tSNE plot) and the scNetViz results (functional networks), it would be good that the UMAP is colored by the original clustering (k.sel = True) found in Categories. This way, biologists could do a figure with the UMAP and below the networks or the enrichment results for each of this cluster.