Update the relevant notebook with a stand alone dataset download

[Idan-BenAmi]

Pull Request Description:

Update the Keras PTQ notebook with a dataset download and make additional minor modifications.

Checklist before requesting a review:

• I set the appropriate labels on the pull request.
• I have added/updated the release note draft (if necessary).
• I have updated the documentation to reflect my changes (if necessary).
• All function and files are well documented.
• All function and classes have type hints.
• There is a licenses in all file.
• The function and variable names are informative.
• I have checked for code duplications.
• I have added new unittest (if necessary).

[elad-c]

1. Add comments for all files, same as in the effdet tutorial
2. Consdier merging consecutive "markdown" cells to a single cell