manual tour, "ink_tank" slider for animation

[nspyrison]

Would be a slider from [0, 1] defaulting to the initial basis,

-first frame would be 0 contribution,
-last frame would be max contribution
-START frame would display at initial basis, ideally with a reminder on the slider
-Doesn't make sense for gganimate, has to be plotly or shiny.
-Require an alternative manual_tour or at least reordering there of