26902 Initial code review

Created a branch from the very first commit to be able to review the whole code written so far.
This does not mean that a merge should be done after the review is done, this is a "dummy" pull request.
Should be 
```
(return_code, widget) = start_qt_app_and_show_modal(
    "Create Flame Project",
    self._engine,
    etc, 
    etc,
)
```