add ability to import scrivener dictionary

Harper has the ability to import a dictionary. Scrivner has an internal dictionary

I assume that scrivener's dictionary to part of a file's metadata? You can export and saves local files settings to transfer to other scrivener files so I think Harper just needs to be able to read this

Start by determining the format produced when Scrivener exports its internal dictionary and compare it with Harper's existing dictionary import capability. Done means a Scrivener-exported dictionary can be imported successfully and its words are available to Harper.

Written by the indexing model from the issue text.