Mv interfaces -> widgets/lib/interfaces

[mishig25]

As discussed in #202, moving interfaces folder to widgets/lib/interfaces

What's been done:

1. Move all files from interfaces to widgets/lib/interfaces & delete original interfaces folder
2. Update workflows for Github actions, updating widgets/lib/interfaces path
3. Update readmes, updating widgets/lib/interfaces path

[Pierrci]

Thanks @mishig25!

Can you open a small PR in moon-landing to reflect the changes in paths once you merge this one? (you'll also need to update the huggingface_hub submodule)

I know this will be rendered obsolete soon once we switch to package import but until then... :)