As a content editor, I want footnotes to indicate when a digital edition is available so that I can see and filter on records with and without transcription in the admin interface.

[rlskoeser]

testing notes

• in admin, footnotes now have a "digital edition" document relation type
• in admin, test filtering documents by "has transcription"
• add a new transcription to a document that did not previously have one; confirm that a digital edition footnote was automatically created (testing may overlap with other issues, e.g. adding a new transcription falls under As a content editor, I want to create a new transcription linked to new or existing scholarship records so I can document its source and authorship. #1002) and that there is a log entry documenting the creation
• delete the last transcription section for a document; confirm that the digital edition footnote was removed and that there is a log entry documenting the change

dev notes

• update the footnote model to remove the interim content field and add a new boolean has_transcription (replaces the existing property)
• add a signal handler that listens to annotation save events and updates the footnote appropriately when new transcriptions are added or all transcriptions are removed
• update admin list views, filters, etc as needed

[kseniaryzhova]

@rlskoeser There is no log entry created when we added and saved a new transcription (https://test-geniza.cdh.princeton.edu/admin/corpus/document/19696/change/). The transcription itself was saved and displayed correctly, and a footnote labelled "digital edition" was created.

[rlskoeser]

@kseniaryzhova ah, sorry! my testing instructions were vague, there should be a log entry for the footnote, not on the document