feat: Add uspto backend meta-data extraction

[vku-ibm]

Adds extraction of the meta-data for uspto-backend that handles parsing of uspto patents in xml form.

Issue resolved by this Pull Request:
Resolves #2273

Checklist:

• Documentation has been updated, if necessary.
• Examples have been added, if necessary.
• Tests have been added, if necessary.

[github-actions]

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Make sure that we follow https://www.conventionalcommits.org/en/v1.0.0/

• title ~= ^(fix|feat|docs|style|refactor|perf|test|build|ci|chore|revert)(?:\(.+\))?(!)?:

[cau-git]

This @abstractmethod tag should not be necessary since you are providing a default implementation.

[PeterStaar-IBM]

@vku-ibm This is a really good addition! Could you, for the PDF pipelines,

1. Extract the meta-data through the docling-parse metadata extraction methods
2. Add the Table-of-contents from the pdf (if it has any) via docling-parse?