Add tutorial: Connecting ink! Smart Contracts to a React Frontend with PAPI and ReactiveDOT (InkFundMe Example)

[truthixify]

This PR introduces a new tutorial demonstrating how to connect an ink! smart contract to a React frontend using PAPI and ReactiveDOT.

The tutorial uses the InkFundMe crowdfunding dApp as a practical example, showing how to:

• Integrate ink! contract calls in a React app with PAPI
• Leveraging ReactiveDOT, a React integration for building Substrate dApps with PAPI
• Managing contract state, user interactions, and live updates in React
• Handle user interactions such as campaign creation, token contributions, and refunds
• Deploy the contracts to Passet Hub testnet and frontend on Vercel

This serves as a step-by-step guide for developers learning to build interactive frontends for ink! based smart contracts using modern Polkadot tooling.

[cmichi]

@Daanvdplas Can you take a look at this PR? A while ago you had some remarks in Element about using the Assets precompile for this.