Better support for sf data structures in `plot_mapbox()`/`plot_geo()`/`plot_ly()`

[cpsievert]

Perhaps there should be an add_sf() which would ignore trace type/mode etc?

https://github.com/ropensci/plotly/blob/master/demo/sf-data-scattermapbox.R

[harryprince]

which type of sf that mapbox can support? I am trying to use sf::st_multipoint but fail with plotly::group2NA()

[cpsievert]

@harryprince can u give me an example? You shouldn't need plotly::group2NA() to plot points