Instead lets just use the path_provider. This was being used as for some
reason I wanted the files to reside inside the 'files' folder and not in
the 'app_flutter' directory.
However, that requires maintaining a fork of path_provider, which I no
longer want to do.
This required refactoring the code. With this we can now write an
integration test to test the main parts of the app, but more importantly
we can automate the process of generating the screenshots.