Implement describe functionality via client-go apis.

[Tatsinnit]

This is the PR with the intent to move away from kubectl binary and use the go-lang clients for Kubernetes. Improve test coverage/ability for the collectors of this repo as well.

Tested with Image: docker.io/tatsat/pod-describer it gives more data which could be handy.

Thanks,

cc: @arnaud-tincelin , @rzhang628 , @qpetraroia , @palma21 and @JunSun17 and fyi: @sophsoph321

sample logs

[codecov-commenter]

Codecov Report

Merging #120 (70e14fc) into master (118d62a) will increase coverage by 3.67%.
The diff coverage is 72.22%.

@@            Coverage Diff             @@
##           master     #120      +/-   ##
==========================================
+ Coverage   31.46%   35.14%   +3.67%     
==========================================
  Files          12       12              
  Lines         518      515       -3     
==========================================
+ Hits          163      181      +18     
+ Misses        340      317      -23     
- Partials       15       17       +2     

Impacted Files	Coverage Δ
pkg/collector/kubeobjects_collector.go	73.33% <70.58%> (+73.33%)	⬆️
pkg/collector/pods_containerlogs_collector.go	78.78% <100.00%> (+1.01%)	⬆️

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