Nuke 16 Compatibility Update

This PR adds compatibility with Nuke 16, which uses Python 3.11 and PySide6 (not PySide2 as in previous versions).

Changes made:

1. Updated Qt Imports:

   • Added support for PySide6 which is used in Nuke 16
   • Maintained backward compatibility with older Nuke versions
   • Implemented a robust import system that tries multiple Qt frameworks

2. Added documentation:

   • Created README.md with installation instructions
   • Added specific guidance for Nuke 16 users

3. Version update:

   • Updated version to v1.2
   • Updated the date to reflect the changes

Testing:

These changes have been tested in Nuke 16.0v1 with Python 3.11.7, where PySide6 is the available Qt framework (PySide2 is not available in this version).

The updated plugin successfully runs in Nuke 16 while maintaining compatibility with older versions.