Add pod ip address to Kubernetes logs

**Is your feature request related to a problem? Please describe.**

When trying to correlate other logs with logs from a Kubernetes pod it is common that the only identifier you find for the pod in other logs is the ip address. But that is not automatically added by fluent bit which makes the correlation difficult.

**Describe the solution you'd like**

Add the pod ip address to the logs. Following the current convention it could be named k8s.pod_ip.

**Describe alternatives you've considered**

The application itself could log the ip address. But that means extra work on each application.

**Additional context**

I my particular case I want correlate the logs from AWS Application Load Balancer with application logs.