Enable IPFIX export

[praveingk]

This PR address the below issue https://github.com/netobserv/netobserv-ebpf-agent/issues/26 to provide IPFIX export of flow records, which can be consumed directly by any platform.

[mariomac]

Doing an initial view, it looks good! I'll do later a more detailed review.

In the meantime, I think we should add e2e tests. For example, you can just copy the kafka folder into e.g. ipfix and add some modifications:

1- in the manifests/ subfolders, remove the kafka manifests, then configure the flp-transformer and agent manifests to export/accept IPFIX data (FLP already accepts IPFIX)

2- rename the kafka_test.go to ipfix_test.go, remove this lines and this lines.

[praveingk]

Doing an initial view, it looks good! I'll do later a more detailed review.

In the meantime, I think we should add e2e tests. For example, you can just copy the kafka folder into e.g. ipfix and add some modifications:

1- in the manifests/ subfolders, remove the kafka manifests, then configure the flp-transformer and agent manifests to export/accept IPFIX data (FLP already accepts IPFIX)

2- rename the kafka_test.go to ipfix_test.go, remove this lines and this lines.

Thanks Mario, I will add the e2e tests.

[mariomac]

Adding hold labels for the feature freeze.

[praveingk]

@mariomac
I have added e2e tests. Do note that in FLP config, I had to fix "Interface" to a non-zero field, since flp's ipfix input from goflow does not return interface name which was exported by ebpf agent.

[mariomac]

Mostly looks good. I have a suggestion about renaming a struct and a file, and a concern about the performance.