Plots in `DTU` module can also be made interactive

[tbrittoborges]

In addition, individual points can show patient id + phenotype on hover.

[federicomarini]

For the plots themselves: when no gene is selected, we should probably have another message triggered, and not the "gene is not detected as DTU", but rather something like "please select a gene to display the DTU-related content" (of course, here I am paraphrasing, but you get the gist of it, I guess).