Conditional feature for map/unwind middleware

[danielgerlag]

This pull request enhances the middleware documentation by introducing conditional processing capabilities for both the unwind and map operations. It also provides detailed examples to demonstrate the use of these new features in practical scenarios.

Enhancements to Middleware Configuration:

Unwind Operation:

• Added a new condition property to the unwind configuration, allowing selective application of the unwind operation based on the properties of the incoming node.
• Documented an example showcasing how to use the condition property to unwind container statuses only when a specific action (e.g., "update") is detected in Kubernetes Pod events.

Map Operation:

• Introduced a condition property to the map configuration, enabling conditional mapping based on the content of the incoming element.
• Provided an example illustrating how to handle different GitHub webhook event types (e.g., "opened," "closed," and "deleted") using the condition property to route them to appropriate operations.

These updates improve the flexibility and expressiveness of middleware configurations, making them more adaptable to complex, event-driven data workflows.