Support Qt for Python project templates (wizard)

At the moment it's only possible to create a File and a Class in QtCreator for Qt for Python. Providing a default project could improve the user experience, and also will clarify the compatibility with .pyqtc files.

Some templates could be:

• Create empty default project (main.py with base structure)
• Create a default scheme for using UI files
• Create a project scheme (including main.py, some lib directory, etc)
• etc... (ideas are welcome)

Additionally, it could be nice to rename the files ".pyqtc" to something more general like ".pyproject" (following the ".qmlproject" structure name).