The scale of the old icons was inconsistent with the rest of the Font
Awesome kit so I updated the aspect ratio to make it a little narrower.
I also am adding the outline assets to our repo
This adds a new app icon for windows that is less Mac-like and it also
fixes a bug in the electron-builder.config.cjs file which would cause
the packaging step to crash if it was missing the signing env vars,
rather than just not signing the package.
