BTSSS on VA.gov feature reference documentation

[laurenernest]

Issue Description

As a team coordinating feature development across multiple products, we should document where beneficiary travel claims functionality lives on VA.gov.

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Tasks

• [x] Create feature-reference folder under main /beneficiary-travel/ path
• [x] Create README with index shell for future additions
• [x] Create feature toggle documentation
• [x] Create mvp-implementation folder under feature-reference folder
• [x] Create initiative brief shell

Acceptance Criteria

• [ ] All tasks are complete
• [ ] Initial artifacts or paths to artifacts are linked to this ticket

[laurenernest]

• Feature reference folder that includes space for future MVP documents, including the initiative brief: https://github.com/department-of-veterans-affairs/va.gov-team/tree/master/products/health-care/beneficiary-travel/feature-reference
• Feature toggle documentation to track toggles we manage: https://github.com/department-of-veterans-affairs/va.gov-team/blob/master/products/health-care/beneficiary-travel/product/feature_toggles.md