Python: Integrate uic/rcc for Python projects

After many patches, uic and rcc will be Python compatible (for 5.14 hopefully). This means that they will be able to output Python code, that will be possible to use from the PySide module.

Once the changes are in, the PySide module will replace the current implementation of pyside-uic and pyside-rcc for these binaries.

A really nice improvement will be to include the widely-known logic from Qt/C++ projects, into Python, i.e.: We should re-/generate the python source (from the .ui or .qrc file) when it's modified on Qt Creator.