Add SCORM→JSON→DOCX pipeline and reorganize format/pipeline modules

[arolos]

Closes issue #14

1. SCORM → JSON → DOCX conversion flow

• Adds an end‑to‑end pipeline that takes SCORM packages, parses them into the existing JSON question model, and then renders DOCX from that JSON.
• Handles conversion concerns like preserving question structure, formatting, and media so the DOCX output is usable without manual cleanup.

2. API folder restructure

• Moves legacy processing code out of generic buckets into format‑based modules:
  • api/formats/docx/* for DOCX parsing/formatting helpers.
  • api/formats/scorm/* for SCORM parsing/writing helpers.
  • api/formats/scorm/xml_builders/* for SCORM XML builders (per question type).
  • api/questions/model_builders/* for per‑question‑type model builders.
  • api/pipelines/* for explicit conversion entry points.

3. Pipeline helpers + response payloads

• Introduces api/pipelines/response_payload.py for consistent status/response payloads.
• Adds api/pipelines/ws_pipeline.py for the WS progress pipeline.
• Simplifies views/consumers by moving orchestration into pipelines.

4. main_text support

• Adds support for root‑level main content separate from the title.
• That content is carried through the parse/serialize flow and included in the output alongside sections.

5. Cleanup of legacy modules

• Removes deprecated restapi/* and old api/process/* / api/scorm/* files.
• Dockerfile no longer copies the deprecated restapi folder.

[kphunter]

I'm not sure how to verify/test these changes... (other than scanning the code manually 😳 )... Any thoughts?