Update Nextjs Template from 12 to 14

[cd-Roid]

Using the npx @storyblok/create-demo@latest script is very intuitive and helps saving time when spinning up a storyblok project. But its still using Next 12 which is quite old now. It would be great to have the command fufill a better purpose than it s doing right now.

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Expected Behavior

• Command creates a Nextjs Project using "next": "14.2.9" and "react": "^18".
• Project uses the app Router
• Project creates TypeScript files instead of js Files
• Project implements the current tutorial in the Documentation

Current Behavior

• Project uses next 12.
• Project generates js Files
• Project uses Pages Router
• Project uses old Documentation

Steps to Reproduce

1. Create a Storyblok Space in Dashboard
2. npx @storyblok/create-demo@latest Command