Implement ModuleSpecBuilder and support for referenced explanatory sections

[dwikler]

Title:
Implement ModuleSpecBuilder and support for referenced explanatory sections in DICOM Module tables

Description:

• Implement ModuleSpecBuilder to orchestrate parsing of Module tables and referenced explanatory sections.
• Add logic to scan specified columns for section references and parse/store them as SectionSpecModel in a registry.
• Add caching for parsed sections.
• Update documentation and add tests for this new feature.