Use a simple logger wrapper instead of Akka Logging

[aliyakamercan]

@benblack86 @DanSimon @dxuhuang

fixes #409

[codecov-io]

Codecov Report

Merging #571 into develop will decrease coverage by 0.16%. The diff coverage is 54.76%.

@@             Coverage Diff             @@
##           develop     #571      +/-   ##
===========================================
- Coverage    84.69%   84.52%   -0.17%     
===========================================
  Files           98       99       +1     
  Lines         4422     4432      +10     
  Branches       360      357       -3     
===========================================
+ Hits          3745     3746       +1     
- Misses         677      686       +9

Impacted Files	Coverage Δ
...sus/src/main/scala/colossus/service/Callback.scala	88.28% <ø> (ø)	:arrow_up:
.../scala/colossus/metrics/senders/LoggerSender.scala	0% <0%> (ø)	:arrow_up:
.../src/main/scala/colossus/metrics/MetricClock.scala	61.9% <0%> (ø)	:arrow_up:
...cala/colossus/metrics/senders/OpenTsdbSender.scala	0% <0%> (ø)	:arrow_up:
...src/main/scala/colossus/metrics/StatReporter.scala	73.91% <0%> (ø)	:arrow_up:
.../main/scala/colossus/metrics/senders/package.scala	0% <0%> (ø)	:arrow_up:
...rc/main/scala/colossus/service/ServiceClient.scala	91.6% <100%> (-2.8%)	:arrow_down:
colossus/src/main/scala/colossus/core/Worker.scala	76.99% <37.5%> (-0.11%)	:arrow_down:
...ala/colossus/metrics/logging/ColossusLogging.scala	58.33% <58.33%> (ø)
...s/src/main/scala/colossus/core/WorkerManager.scala	87.75% <63.63%> (ø)	:arrow_up:
... and 4 more

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