fix(source/service): disable node informer when not required

[ivankatliarchuk]

What does it do ?

• when --service-type-filter is configured, disable node informer when not required

nodeInformer used in 2 places

• v1.ServiceTypeNodePort (could be safely disabled)
  • extractNodePortTargets
  • nodesExternalTrafficPolicyTypeLocal
• V1. ServiceTypeClusterIP -> added null check, and warning message, so that if informer is disabled but should be enabled
  • extractHeadlessEndpoints

Motivation

Fixes #3169

Follow-up:

• we could exclude certain services from caching/indexing when --service-type-filter is specified. This should increase performance and reduce number of API calls and etc.
• disable pod informer when LoadBalancer is set Unnecessary access to v1.Pod lead to timeout. #4955 and Too many Kubernetes resources will cause "failed to sync *v1.Pod: context deadline exceeded" #3173 and failed to sync *v1.Node (but I didn't request --source=node) #3169 (comment)
• add Node Transformer as in this PR feat: use transformers in pod informers to reduce memory footprint #5596

More

• Yes, this PR title follows Conventional Commits
• Yes, I added unit tests
• Yes, I updated end user documentation accordingly

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[ivankatliarchuk]

Hi @iameli. Not sure if you still interested in the fix. But if yes, can you confirm that this PR fixes your issue. If needed, see how to test a PR ?. This will require golang to be installed.