[DBEX] create Lighthouse526DocumentUpload model with state

[freeheeling]

Summary

Objective: Implements a system for periodically polling the Lighthouse uploads/status endpoint to confirm the status of supplemental documents submitted to Lighthouse as part of a Form 526 Submission. The purpose of this system is to surface successes and failures that happen in the Form 526 process after being forwarded to Lighthouse for processing.

• Create Lighthouse526DocumentUpload model
  • responsible for persisting a record of a document submitted to Lighthouse's Benefits Document API
  • used to track status of a document as it makes its way through VA's systems
  • must be attached to a Form526Submission
    • if referencing a Veteran-submitted document, must also be attached to the FormAttachment record created for the upload
  • lighthouse_document_request_id is required
    • returned from Lighthouse Benefits Documents API as requestId in the response body
    • used to track upload as it passes through Lighthouse's processing
• Subsequent PRs will implement interaction with the Lighthouse Benefits Document API client
• This work is behind a feature toggle (flipper): YES/NO
• Responsible team: Disability Benefits Experience Team 2 (dBeX Carbs 🥖)

Related issue(s)

• [DBEX] create Lighthouse526DocumentUpload migration #17405
• Form 526 Document Upload - Lighthouse status polling system #15964
• [Doc Upload Polling] Implement Migration In Separate PR va.gov-team#87617
• [Epic] Implement Document Upload Polling Solution va.gov-team#75804

Testing done

• New code is covered by unit tests
  • new model's initial state, validations, and state transitions covered in spec/models/lighthouse526_document_upload_spec.rb

What areas of the site does it impact?

• non-user facing, asynchronous job tracking the status of uploaded documents submitted in conjunction with Form 526EZ

Acceptance criteria

• I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• No error nor warning in the console.
• Events are being sent to the appropriate logging solution
• Documentation has been updated (link to documentation)
• No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs
• Feature/bug has a monitor built into Datadog (if applicable)
• If app impacted requires authentication, did you login to a local build and verify all authenticated routes work as expected
• I added a screenshot of the developed feature

[va-vsp-bot]

Error: A file (or its parent directories) does not have a CODEOWNERS entry. Please update the .github/CODEOWNERS file and add the entry for the Offending file: app/models/lighthouse526_document_upload.rb