feat: add simple chat for nextjs template

...s/create-llama/templates/simple/nextjs/README-template.md

...ma/templates/simple/nextjs/app/components/chat-avatar.tsx

...a/templates/simple/nextjs/app/components/chat-history.tsx

...lama/templates/simple/nextjs/app/components/chat-item.tsx

...a/templates/simple/nextjs/app/components/chat-section.tsx

...e-llama/templates/simple/nextjs/app/components/header.tsx

...a/templates/simple/nextjs/app/components/message-form.tsx

...ages/create-llama/templates/simple/nextjs/app/favicon.ico

...ages/create-llama/templates/simple/nextjs/app/globals.css

packages/create-llama/templates/simple/nextjs/app/page.tsx

...mplates/simple/nextjs/app/services/chatStorage.service.ts

...ges/create-llama/templates/simple/nextjs/public/llama.png

...ages/create-llama/templates/simple/nextjs/public/next.svg

...es/create-llama/templates/simple/nextjs/public/vercel.svg