ALTO upload: Make sure images are checked after creation

There have been some issues related to image dimensions while uploading ALTO documents.

The images were not correctly checked after the call to CreateIIIFURL. When that works, we should add an assertion rule on the "status" of the image. Depending on its value:

• "checked": move on
• "error" or unchecked": try at most 5 times to have "checked" by calling PartialUpdateImage with "status": "checked". After the 5th try, if it's still not ok, error log + raise an UploadProcessingError

Refs https://redmine.teklia.com/issues/9833