[feature request] choose multiple puzzle themes at ones

[SKOHscripts]

Some platforms make it possible to select several puzzle themes and play them randomly within the same puzzle series.

It would be great to have this feature.

A nice to have would be to randomly play these selected puzzle themes and give a higher appearance factor for the puzzle themes you're least good at (perhaps an increasing appearance factor as the themes move further and further away from the average).

[Boubou78000]

If it is not implement in the website, open an issue on Lila first.