Refine architecture for deferred proofing via SIS & Lighthouse

[alevindecanini]

Issue Description

We need to complete the architecture and design analysis and decompose it into clearly defined stories.

---

Tasks

• [ ] Analyze the deferred proofing architecture and create stories for the tasks related to SiS and Lighthouse.

Acceptance Criteria

• [ ] github stories created with Tasks and Acceptance criteria

[sdickson-gt]

VA Mobile / SiS - Joe and core team provided a high-level breakdown of tasks to support deferred proofing. Need to revisit for better understanding.
whimsical board: https://whimsical.com/grandfathering-6YXbgNggbdGiv8wLEfznVP Note on all deferred proofing tasks in whimisal: some of the other tasks (besides SiS) will have already been completed for the organic modal, but will need tweaked for deferred proofing, e.g. GA metrics and content.

Lighthouse (Okta) - tbd impact and what if any support would be required

[alevindecanini]

@sdickson-gt can you please help fill in the description, tasks, and acceptance criteria for this ticket?

[alevindecanini]

@sdickson-gt when does this need to be completed relative to other deferred proofing tasks?

[alevindecanini]

Please add your planning poker estimate with Zenhub @sdickson-gt

[sdickson-gt]

We could go live with deferred proofing on just USiP. These are needed for a more comprehensive solution covering SiS and Lighthouse entry points. This is dependent unblocking risks for deferred proofing and IAM implementation of binding accounts.