K8s Processor: logs support

[pmm-sumo]

Description: Adds log support to k8sprocessor

Link to tracking Issue: open-telemetry/opentelemetry-collector#1654

Testing: unit tests cover logs use-cases, manual tests via fluentforward protocol done (and spans to confirm nothing breaks)

Documentation: updated doc.go and cleared-out (hopefully) how is the pod IP address determined

[codecov]

Codecov Report

Merging #1051 into master will increase coverage by 0.01%.
The diff coverage is 90.90%.

@@            Coverage Diff             @@
##           master    #1051      +/-   ##
==========================================
+ Coverage   88.81%   88.83%   +0.01%     
==========================================
  Files         250      250              
  Lines       11924    11945      +21     
==========================================
+ Hits        10590    10611      +21     
  Misses        990      990              
  Partials      344      344              

Flag	Coverage Δ
#integration	75.42% <ø> (ø)
#unit	87.85% <90.90%> (+0.02%)	⬆️

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Impacted Files	Coverage Δ
processor/k8sprocessor/processor.go	89.28% <66.66%> (-2.72%)	⬇️
processor/k8sprocessor/factory.go	97.33% <100.00%> (+0.66%)	⬆️
receiver/k8sclusterreceiver/watcher.go	97.64% <0.00%> (+2.35%)	⬆️

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[tigrannajaryan]

@keitwb @owais please review.

[keitwb]

LGTM

[pmm-sumo]

While working on this PR I noticed two things:

• Shouldn't we move the config description from doc.go to README.md (as for other processors)? There is a closed issue on that but I am not sure if it has the originally intended outcome: K8S processor: Add detailed user documentation #97
• Perhaps we could extract some of the hardcoded behaviour into config entries: K8S Processor: configure the list of ignored pod names #1077, K8S Processor: configure ip extraction using incoming connection source IP #1078, K8S Processor: configure tag name with source of the IP address #1079, K8S Processor: record-level tagging #1080

Let me know what do you think, those should be quick to add if they make sense

[bogdandrutu]

Shouldn't we move the config description from doc.go to README.md (as for other processors)? There is a closed issue on that but I am not sure if it has the originally intended outcome: #97

Using README is more consistent

Perhaps we could extract some of the hardcoded behaviour into config entries: #1077, #1078, #1079, #1080

Sounds like a good idea