Add configuration that allows identification of Pods by L2 infomration

[eranra]

We want to make it possible to use L2 information ( MAC addresses) to identify pods and not just L3 (what we have today). This requires changing the informer https://github.com/netobserv/flowlogs-pipeline/blob/main/pkg/pipeline/transform/kubernetes/kubernetes.go#L180 so that it can match pods by mac addresses and not just by IPs. This needs to be configurable so that it will be possible to use just IP's, Just MAC addresses or both for the identification.

[amorenoz]

Note on some CNIs (e.g: OVN-k8s) packets can be routed so on destination switch the source MAC address will not match the one from the src pod.