Draft deliverable spec for cross-program product strategy

[widal001]

Summary

Draft a deliverable spec for the Cross-program product strategy (Base Year 1) deliverable (HHS/simpler-grants-gov#2356) using the outline from Appendix A in the SWIFT call order.

Acceptance criteria

• The draft spec has been created in Google docs and shared with the team for feedback
• The reviewed spec has been moved into the associated GitHub ticket: Cross-program product strategy (Quad 2) simpler-grants-gov#2356

[widal001]

Initial draft of the deliverable was shared and reviewed by @lucasmbrown-usds and I moved the content into the deliverable ticket.

Additional refinement of proposed metrics may be scoped into a follow-up ticket for sprint 1.3