Lazy popup - only load content on click

[marciogranzotto]

Fixes #1214

2021-09-04.18-19-23.mp4

Usage:

marker = folium.Marker(
    [data['Latitude'], data['Longitude']],
    popup=folium.Popup(data['popup_html'], lazy=True),
    tooltip=tooltip,
    icon=folium.Icon(color=data['color'])
)

[labtec901]

Bumping to express how useful I think this change is. I published a repo today for one of my scripts and I am directing users to this open pull request to get the updated .py file because my application is prohibitively slow without this functionality.

[Conengmo]

Thanks @marciogranzotto!