Handling object which has multiple images but no image stack

[glenrobson]

Fixes #52

Manifest: https://internetarchive-iiif-issue-52.ux-fnf-misc.archive.org/iiif/3/arkivkopia.se-lms-G70-48.3/manifest.json

[glenrobson]

For discussion regarding the fix to #46. I got to the point where the manifest was generating but the images were invalid according to Cantaloupe. I've implmeented the following:

https://internetarchive-iiif-issue-52.ux-fnf-misc.archive.org/iiif/3/st-anthony-relics-01/manifest.json

Which adds a canvas for each missing image but up for disucssion wether this is the correct behaviour. Should it just fail?

It follows the structure in the missing image recipe: https://preview.iiif.io/cookbook/0283-missing-image/recipe/0283-missing-image/

[digitaldogsbody]

Retargeted because I remembered about the issue with branches that have underscores

[glenrobson]

It looks like the manifest in #46 is now working and has 5 images:

https://internetarchive-iiif-issue-52.ux-fnf-misc.archive.org/iiif/3/arkivkopia.se-lms-G70-48.3/manifest.json

but the item now has a number of PDFs and is a complex object:

https://archive.org/details/st-anthony-relics-01/

I think its probably safe to close #46 and merge this as it fixes the original issue.

[glenrobson]

Strange issue with manifest in Mirador and issue with thumbnails:

https://projectmirador.org/embed/?iiif-content=https://internetarchive-iiif-issue-52.ux-fnf-misc.archive.org/iiif/3/arkivkopia.se-lms-G70-48.3/manifest.json

Issue with this manifest is that all the canvas ids are the same!