feat: add metric prefix config and expose metricCollectors

[Abdulsametileri]

If one application uses multiple kafka konsumer instances, they cannot use Prometheus metrics because they have collusion, their names are same. To prevent this kind of situation, we enable a metricPrefix config.

In prometheus, it is not possible to register exact two metrics. Prometheus gives panic: duplicate metrics collector registration attempted error message.

[codecov]

Codecov Report

Attention: 14 lines in your changes are missing coverage. Please review.

Comparison is base (bce9002) 41.56% compared to head (e499f42) 43.31%.

Files	Patch %	Lines
consumer_base.go	0.00%	7 Missing ⚠️
collector.go	85.00%	3 Missing ⚠️
batch_consumer.go	0.00%	2 Missing ⚠️
consumer.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##               v2     #106      +/-   ##
==========================================
+ Coverage   41.56%   43.31%   +1.75%     
==========================================
  Files          19       19              
  Lines         729      741      +12     
==========================================
+ Hits          303      321      +18     
+ Misses        415      409       -6     
  Partials       11       11              

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