Add a utility class that provides fabric8-style wait functionality for
Kubernetes resources. Features include:
- waitUntilReady: wait for resource to pass Readiness check
- waitUntilCondition: wait for custom predicate to be satisfied
- waitUntilDeleted: wait for resource to be removed
- Async variants returning CompletableFuture
- Configurable timeout and poll intervals
- Integration with GenericKubernetesApi

Also adds comprehensive unit tests covering timeout behavior,
condition polling, and async operations.