Fix deleting unused images

[julesvirallinen]

closes #391

There was a bug in publisher where it URI encoded the image path, causing images not to be deleted.

The new publication center also did not include images.

Both issues are fixed.

[oleeskild]

Thank you 🙌 Can you resolve the merge conflicts that is now a thing after accepting the other PR?
Also, I think this causes an issue. If two published notes are embedding the same image, we don't want to delete the image. This means we can't really delete an image before checking every single other published note.

A potential fix for this could be to always append the note path behind the image when uploading to github. We would then risk having duplicate images. But I think trading more storage use for faster publishing is a better solution. Storage is cheap (or in this case, free).

What do you think?

[julesvirallinen]

@oleeskild of course, I prefer to revase onto target branch as it feels cleanest, don't mind doing it ever

Not sure that's an issue, ill see if I can recreate in test garden