Download for canvas seeAlso files

[datazuul]

Add download options, if a canvas has associated seeAlso resources, e.g. hOCR:

example manifest with hOCR:
https://api.digitale-sammlungen.de/iiif/presentation/v2/bsb11659582/manifest

"seeAlso":{"@id":"https://api.digitale-sammlungen.de/ocr/bsb11659582/15","profile":"http://kba.cloud/hocr-spec/1.2/"}

[krkabol]

Hi, let me support this issue - to have an option add a canvas-specific download link(s). I see also a "metadata" or "related" properties in manifest as possible candidates where to store the such link data.

TIA!