Create code to introduce developers to using genkit

[MaesterChestnut]

P0

• [x] Create menu/basic pulling from the existing menu section https://github.com/firebase/genkit/pull/57
• [x] Replace genkit init output with "menuSuggestionFlow" & modify documentation for Getting Started https://github.com/firebase/genkit/pull/62
• [ ] Create menu/generation example https://github.com/firebase/genkit/pull/107
• [x] Create the menu/rag sample with a local db https://github.com/firebase/genkit/pull/82 P1
• [ ] Create a menu/firebase sample with auth, deployment, and firestore vector
• [ ] Create the menu/evaluation sample with genkit evaluators P2
• [ ] Create the menu/express sample
• [ ] Create the menu/telemetry sample
• [ ] Create the menu/multi-step sample
• [ ] Create gif for tour through Developer UI with menu sample