I've added a lot more mock imports so the automatic documentation now works.
I've updated the links between pages (removing .rst extension) so they work.
I've added a link to the settings pane image.
A first pass of documentation describing the web app GUI. Screenshots
are committed as LFS objects, I've been deliberately conservative here
(only png files in the docs/ directory are LFSed) to avoid messing
with any static files in the web app.