Add cluster export and t-SNE caching - #542

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Couple questions without looking at the code yet:

1. We already export the predicted cluster, right?

2. What is the use case for exporting the T-sne coordinates? I'm struggling to see one because they don't mean anything and are not fixed for a dataset. Weighing that with potential UI clutter makes me thing whether we really need it.

1. The cluster prediction yes, not it also exports the probabilties.
2. We got request for the t-SNE export because its apparently useful to have the values if you want to plot them outside of the module/use for later analyses (I do not remmember the exact usecase). (and since I was doing that, I thought that the soft membership might also be nice to have).

I agree with the clutter worry, thats why I changed the group into a collapsed section now:

In many other analyses we are often asked to export more values into the dataset (i.e., residuals, random effects etc... since people wanna do custom things with them) and having a separate section for those things is quite nice.