v0.2.0: Document Extraction Adapters

What's Changed

Adds a suite of adapters for open/document-extraction schema.

Export/Import:

• .txt - Plain text
• .md - Markdown (somewhat RAG optimized)
• .html - HTML
• .hocr.html - The hOCR standard: https://en.wikipedia.org/wiki/HOCR
• .tsv - Tab Separated Values

Full Changelog: v0.1.0...v0.2.0