OKR4-2: Document MVP Requirements for website projects

[celestehorgan]

Problem: When we get requests for website help, we don't have a solid "definition of done", so team members tend to get wrapped up in many-months cycles with projects and handoff takes time.

Proposed solution: Create a document in this repo that specifies what a "complete" website looks like at different stages of project maturity. Provide examples based on existing projects. When new projects come in, evaluate against this definition of done.