Add names and colormaps (via LayerDataTuple) to the output layers

[psobolewskiPhD]

The plugin implements 3 different decompositions. Applying colormaps to the output decompositions makes them easier to interpret (and stand out more vs. the data).
PCA and ICA return both positive and negative values, so it makes sense to visualize using a diverging colormap. napari implements PiYG, which is colorblind-safe, so that one is used by default.
NMF specifically does not return negative values, so viridis a uniform, colorblind-safe colormap is used by default.
Also, the layers are named explicitly.

[zoccoler]

Hi Peter @psobolewskiPhD,

This implementation make total sense to me, good idea!
I also like the flexibility of the LayerDataTuple return annotation.
I can confirm the changes work here.

Best,
Marcelo