refactoring eniconfig func to only take node as parameter

[haouc]

What type of PR is this?
Refactor a function in eniconfig package

exposing an API to VPC resource controller
Which issue does this PR fix:

What does this PR do / Why do we need it:
This PR refactor the function GetNodeSpecificENIConfigName which can exposes an API for VCP resource controller to call as a dependency.

If an issue # is not available please add repro steps and logs from IPAMD/CNI showing the issue:

Testing done on this change:

custom networking labels were tested after refactoring.

% k get no -oyaml | grep eniConfig
      vpc.amazonaws.com/eniConfig: us-west-2b
      vpc.amazonaws.com/eniConfig: us-west-2b
      vpc.amazonaws.com/eniConfig: us-west-2a
      vpc.amazonaws.com/eniConfig: us-west-2b

Automation added to e2e:

no change on functionality
Will this PR introduce any new dependencies?:

no
Will this break upgrades or downgrades. Has updating a running cluster been tested?:
no

Does this change require updates to the CNI daemonset config files to work?:

no
Does this PR introduce any user-facing change?:

no

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[FernandoMiguel]

not sure if related, but this is the only change regarding ENIConfig i could find in vpccni v1.13
on v1.12 this works fine.
on 1.13 we are seeing issues when applying terraform

Error: us-east-1a failed to fetch resource from kubernetes: the server could not find the requested resource
  with module.base_system.kubectl_manifest.eni_config["subnet-XXXX"],
  on .terraform/modules/base_system/cni_custom_networking.tf line 5, in resource "kubectl_manifest" "eni_config":
   5: resource "kubectl_manifest" "eni_config" {

is there a chance this change introduced a breaking change @haouc @jdn5126 ?

[jdn5126]

@FernandoMiguel are you using ENIConfigs without any security group specified? This was one known bug between v1.12.x and 1.13.0: #2426

If this is not the case, or if you are using v1.13.2, let's open a new issue or connect on #aws-vpc-cni on k8s Slack

[FernandoMiguel]

@jdn5126 there is one sg per ENI config.
I'll jump on slack tomorrow

[FernandoMiguel]

after further investigating this, seems we are being affected by this instead
gavinbunney/terraform-provider-kubectl#270
sorry to have bothered you

[jdn5126]

@FernandoMiguel no worries, glad you have a root cause!