When generating the gallery automatically, the structure
of the examples was not the same for all the modules.
This reorganization was made under the following assumption:
An example requires:
- its own directory,
- a '.pyproject' file,
- one or more '.py' files,
- extra files (likes images, .rc, .ui, etc)
Even for cases when subdirectories are made to depict categories, like
'widgets/state-machine/...', one directory is required per example.
There should not be '.pyproject' files for categories,
except for the general 'examples.pyproject' to open all of them.
Reviewed-by: Cristian Maureira-Fredes <firstname.lastname@example.org>