Add tiny-iiif-manifest-authoring-tool

[hadro]

I haven't tried this out, but the demo makes it look like a pretty simple and useful GUI means for creating IIIF manifests:

• Code: https://github.com/yuta1984/tiny-iiif-manifest-authoring-tool
• Demo: https://twitter.com/yuta1984/status/1685581815501737985