Consolidate Extensions app code in a single place
The goal for 3.36.1 is to untie the exension app from core gnome-shell, move it to a subproject like we did for the extensions-tool, and ultimately put it up on flathub.
Not spreading the app between src, js and data is a first step towards that.
Fixes #2302 (closed)
Edited by Florian Müllner