Add FlowBox and FlowBoxChild widgets

[sudoharun]

Feature Description

The advantage of using FlowBox instead of Grid is that I can dynamically add and remove content (either literally removing them or by toggling visibility).

For example, I have an Ethernet and a WiFi button, both in a grid layout. Each of them dynamically set their visibility based on their connection status.

The issue is that the last visible widget before an invisible widget takes up the space of the invisible widget, so if I have a column_num of 2 (regardless of column_homogenuous) and I only have 2 children in the grid, if the last child is invisible, the first child will take up 2 columns

[newor0599]

i think a combination of revealer and .remove_child/.append_child will satisfy you, thats how i do it