Progress bar can exceed Jupyter's data rate limit

[helena-intel]

When downloading a large file with download_file (from notebook_utils), depending on system and download speed, Jupyter may show errors about the data rate limit being exceeded. This fails the notebook in the CI, and is also visible in the notebook when running manually.

Setting the progress bar to only display every N blocks helps - I do not see the issue anymore on Linux and Windows when the progress bar is updated every 20 blocks - but on macOS even with every 50 blocks I still saw the issue. We should make the progress bar more robust.

When this is fixed, the progress bar should be added back to the 105 notebook.

[helena-intel]

Fixed in #261