Update OV quantization docs and QA notebook according to the recent changes

[nikita-savelyevv]

What does this PR do?

Follow-up to #638:

• Update OV PTQ documentation
• Update QA model quantization notebook
• For backward compatibility, change quantization config creation logic so that PTQ will be applied if quantization config was not provided explicitly, but calibration dataset was provided.

Before submitting

• [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• [ ] Did you make sure to update the documentation with your changes?
• [ ] Did you write any new necessary tests?

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[nikita-savelyevv]

FYI @AlexKoff88 @l-bat @ljaljushkin