Refactor: support merging extracted layout with inferred layout

[christinestraub]

Summary

This PR is the second part of pdfminer refactor to move it from unstructured-inference repo to unstructured repo, the first part is done in Unstructured-IO/unstructured-inference#294. This PR adds logic to merge the extracted layout with the inferred layout.

The updated workflow for the hi_res strategy:

• pass the document (as data/filename) to the inference repo to get inferred_layout (DocumentLayout)
• pass the inferred_layout returned from the inference repo and the document (as data/filename) to the pdfminer_processing module, which first opens the document (create temp file/dir as needed), and splits the document by pages
  • if is_image is True, return the passed inferred_layout(DocumentLayout)
  • if is_image is False:
    • get extracted_layout (TextRegions) from the passed document(data/filename) by pdfminer
    • merge extracted_layout (TextRegions) with the passed inferred_layout (DocumentLayout)
    • return the inferred_layout (DocumentLayout) with updated elements (all merged LayoutElements) as merged_layout (DocumentLayout)
• pass merged_layout and the document (as data/filename) to the OCR module, which first opens the document (create temp file/dir as needed), and splits the document by pages (convert PDF pages to image pages for PDF file)

This PR also bumps unstructured-inference==0.7.17 since the branch relay on pdfminer refactor from unstructured-inference.

Note

This PR also fixes issue #2164 by using functionality similar to the one implemented in the fast strategy workflow when extracting elements by pdfminer.

TODO

• image extraction refactor to move it from unstructured-inference repo to unstructured repo
• improving natural reading order by applying the current default xycut sorting to the elements extracted by pdfminer

[benjats07]

LGTM!