Prefix pod labels and annotations scraped by prometheus input plugin

[imranismail]

Feature Request

Namespace kubernetes labels and annotations tags scraped by prometheus plugin so that it is easier to exclude it using tagexclude.

Proposal:

Prefix annotation and label tags so that it is easier to process the tags by it's prefix

[[inputs.prometheus]]
  metric_version = 2
  monitor_kubernetes_pods = true
  pod_scrape_scope = "node"
+ pod_label_template = 'pod.label/{{ . }}'
+ pod_annotation_template = 'pod.annotation/{{ . }}'
+ tagexclude = ["pod.annotation/*"]

Current behavior:

<label>=<value>
<annotation>=<value>

Desired behavior:

pod.label/<label>=<value>
pod.annotation/<annotation>=<value>

Use case

[[inputs.prometheus]]
  metric_version = 2
  monitor_kubernetes_pods = true
  pod_scrape_scope = "node"
  tagexclude = ["pod.annotation/*"]

[powersj]

next steps: update the PR and continue the review process

[redbaron]

I believe this is now resolved with #12851