[Napari HUB cli] Metadata enhancement

[seankmartin]

Hi again,

I'm Sean, and I created this issue to complement #5.

While scanning your repository, I identified some metadata that are either missing, follow an unexpected format, or are located in secondary/deprecated sources.

Since metadata sometimes is hard to fix automatically I created a list of what improvements you might want to look into to improve the overall quality of your napari hub listing:

• 'Screenshot/Video' entry was not found or follows an unexpected format (scanned files: README.md, setup.py, pyproject.toml)
• 'Labels' entry was not found or follows an unexpected format (scanned files: .napari-hub\config.yml)

If you need more details about: 'Screenshot/Video', you can refer to this documentation page.
If you need more details about: 'Labels', you can refer to this documentation page.

As I mentioned in my PR, if some metadata is already present and I overlooked it, please feel free to contact me or neuromusic to tell us what could be improved!

Thank you for your help and feedback,

The napari hub and MetaCell teams.