Supporting no-code Guardrail creation

[lucasgomide]

This PR introduce No-Code Guardrail Support

• Enables defining guardrail tasks without requiring explicit code
• Emit events when Guardrail's process has started and competed

Usage

Write down what your guardrail expectation

...
task = Task(
    description="Extract the latest new from BBC",
    expected_output="A JSON object with the latest news",
    guardrail="Ensure the JSON response has more than 10 items",
)
...

If you need more customization such as custom LLM, you can define a GuardrailTask instance

...
task = Task(
    description="Test task",
    expected_output="Output",
    guardrail=GuardrailTask(description="Ensure the JSON response has more than 10 items", llm=llm),
)
...

[lucasgomide]

@gvieira suggestions applied, could you review it again?