Add a custom icon for Extensions

Hey, everything is in the title.

I know i can select icons from the “Resources” folder (i don’t know where it is, but it’s not based on my game Resources folder) but i would like to choose a custom made icon.

Maybe it’s a button i missed.

I think only the icons from the collection included in GDevelop can be chosen. If you really need a custom made icon and know how to convert a SVG in base64, it can be set in the extension json directly.