[Epic] Implement Document Upload Polling Solution

[NB28VT]

Acceptance Criteria

• Add new LighthouseDocumentUpload model, migration and validations
• Build service object to parse Lighthouse Status response
• Build Update service for wrapping interaction with Lighthouse API, parsing service (started)
• Hook into existing Lighthouse Benefits Document API client for querying new endpoint
• Build chron job for kicking off update service
• Set up and run tests to API interaction, run live and record with VCR

[NB28VT]

Work on this is on hold pending an ongoing investigation into handling Veteran communication/visibility for document failures in the current system.

While there are still some loose ends left on this, the core of this work is done and PRed in a draft here. More information in that PR

[lisacapaccioli]

Polling information (getting a status on the uploads after sent to LH to confirm if they make it to the eFolder) (this is before we migrate to LH) - maybe includes alerts/monitoring