Remove custom FindPySide2.cmake, rely on normal packaging

* It seems PySide2 packaging is much more stable now, so we can generally rely
  on the distro packages.

qrenderdoc/Code/pyrenderdoc/PythonContext.cpp

@@ -40,7 +40,6 @@
 // warning C4522: 'Shiboken::AutoDecRef': multiple assignment operators specified
 #pragma warning(disable : 4522)
 #include <pyside.h>
-#include <pyside2_qtwidgets_python.h>
 #include <shiboken.h>
 
 PyTypeObject **SbkPySide2_QtCoreTypes = NULL;