Add DjVuXML converter

[hason]

DjVuXML describs the metadata, hyperlinks, and hidden text associated with the DjVu/PDF file. DjVuXML file is used for the text layer in https://github.com/internetarchive/bookreader

[pietermarsman]

Hi @hason,

Could you describe in more detail what this entails? How would the output look? What should be included or excluded? What is the specification to output should adhere to.

[pettzilla1]

HI @hason and @pietermarsman the licence of the package is copyleft, Judging that pull request #744 focused on removing the copy left packages I feel adding this package would be a step backwards for the package if there is an alternative with no copyleft licence or dependencies , this would be workable

[pietermarsman]

Closing because lack of response.