Write DerivativeRodeo::Generators::WordCoordinateGenerator

[jeremyf]

This builds from the IiifPrint::TextExtraction::AltoReader#json logic. It assumes that we’re building from the derived hocr file.

However, an Alto file need not generate from a hocr file; and could instead be generated via Tesseract.

Depends on:

• I145 update date widget adventist-dl#2

Related to:

• Conditional Derivatives: Inject module into registered to override function utk-hyku#343
• EPIC: Import Optimization with Out of Band Processing adventist_knapsack#421