Add gRPC Health Checking Protocol support

[yanivagman]

Summary

Add support for the standard gRPC Health Checking Protocol (grpc.health.v1) to Tracee's gRPC server.

Motivation

Tracee exposes health checks only via HTTP /healthz. Adding the standard gRPC health service enables:

• Native Kubernetes gRPC health probes (stable since v1.24)
• Compatibility with grpcurl and grpc-health-probe
• gRPC load balancer health checks

References

• gRPC Health Checking Protocol
• Kubernetes gRPC Probes