Frontpage animations

[markotoplak]

On the frontpage, we discussed that long-term we want first two feature images, namely:
(1) animation that builds the workflow and
(2) anamation that selects in the HC widget and then selections in T-SNE change

We already agreed on the workflow a year ago. Notice that, on the current page, the widgets in "Interactive visualizations" are the same as in "Visual programming"

[markotoplak]

I think @larazupan would do this nicely.