added ReadingOrder model

[PeterStaar-IBM]

Checklist:

• Commit Message Formatting: Commit titles and messages follow guidelines in the
  conventional commits.
• Documentation has been updated, if necessary.
• Examples have been added, if necessary.
• Tests have been added, if necessary.

[mllife]

How is this this reading order different from the one used in "docling" postprocess?

Can you explain both the approaches? or give some resources to provide details on these?

[mergify]

Merge Protections

Your pull request matches the following merge protections and will not be merged until they are valid.

🔴 Enforce conventional commit

This rule is failing.

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)(?:\(.+\))?(!)?:

🔴 Require two reviewer for test updates

This rule is failing.

When test data is updated, we require two reviewers

• #approved-reviews-by >= 2