Add workflow to run DPF operator doc update on PR to branch

[PProfizi]

📝 Description of the feature

Add a workflow to run the script updating the DPF operator documentation files based on change to -upd files.

trigger only if:

• no label DPF-no-update-op-desc -> label used by TFS pipeline which already uses -upd files since it runs generate_operators_doc.py
• -upd files were changed or added -> use-case for external collaborations which do not run generate_operators_doc.py

💡 Steps for implementing the feature

No response

🔗 Useful links and references

No response

[PProfizi]

Closing as the decision was made to store updated sources here. The generation script will take care of using -upd files.