Update README steps

[cgcardona]

• Cloning repo
• Checking out hello-world-example branch
• Install NodeJS dependencies
• Create a new contract based on IHelloWorld.sol
• Install the solc dependency
• Generate an ABI and list flags
• Example command to generate precompile files

[ceyonur]

We can use some clarification here.

Suggested change

	Copy the existing `IHelloWorld.sol` interface to a new file called `IHolaMundo.sol`.
	`hello-world-example` branch has already a precompile contract called `HelloWorld.sol`. All necessary files are already created for you. You can check existing files and see how a fully implemented precompile should look like. If you'd like to redo steps to create a new precompile contract, you can follow the steps below.
	Copy the existing `IHelloWorld.sol` interface to a new file called `IHolaMundo.sol`.