Add initial logging

[vlovgr]

Fixes #108.

[codecov]

Codecov Report

Merging #113 into master will decrease coverage by 3.42%.
The diff coverage is 58.58%.

@@            Coverage Diff             @@
##           master     #113      +/-   ##
==========================================
- Coverage   98.02%   94.59%   -3.43%     
==========================================
  Files          38       40       +2     
  Lines        1011     1091      +80     
  Branches       61       69       +8     
==========================================
+ Hits          991     1032      +41     
- Misses         20       59      +39

Impacted Files	Coverage Δ
src/main/scala/fs2/kafka/KafkaConsumer.scala	100% <100%> (ø)	⬆️
src/main/scala/fs2/kafka/internal/syntax.scala	100% <100%> (ø)	⬆️
src/main/scala/fs2/kafka/internal/LogEntry.scala	32.14% <32.14%> (ø)
src/main/scala/fs2/kafka/internal/Logging.scala	46.15% <46.15%> (ø)
.../scala/fs2/kafka/internal/KafkaConsumerActor.scala	90% <67.39%> (-4.69%)	⬇️

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