Docs: Creating a Fuel dApp

[arboleya]

Transform the current Quickstart into a tutorial to build a simple app.

We must show how to leverage our tooling and use the create fuels CLI to scaffold a new full-stack dApp. We also need to go over the generated code and explain what everything is doing.

We should also think of an alternate step-by-step to achieve the same as the scaffolded app.

For example:

1. Write a sample contract
2. Build your contract
3. Running local node
4. Deploying contract
5. Generating types
6. Calling contracts
   • 👉 In the last section, we can have a cross-link that ties it back with the rest of the docs