Build receivers based on new configuration

[tigrannajaryan]

• Build receivers and plug them into pipelines.

• Added tests to verify that single pipeline and multiple pipeline (fan out)
  per receiver work correctly.

• Disable -v flag in go test to reduce unnecessary noise in output, we have
  too many tests to use -v flag. Errors are still properly printed. This makes
  finding the cause of test failures easier.

• Add logging to various application startup steps.

• Changed logging from %q to %s in multiple places to make it more human readable
  when output in json format.

Testing done:

1. make && all unit tests pass.

2. make otelsvc and produce otelsvc_linux executable.

3. Manually verify that otelsvc_linux runs and correctly forwards trace data
   received via jaeger receiver and exported via opencensus exporter.

   This is the first successful run of unified OpenTelemetry Service.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@2a40f54). Click here to learn what that means.
The diff coverage is 69.5%.

@@            Coverage Diff            @@
##             master      #25   +/-   ##
=========================================
  Coverage          ?   68.95%           
=========================================
  Files             ?       82           
  Lines             ?     5463           
  Branches          ?        0           
=========================================
  Hits              ?     3767           
  Misses            ?     1480           
  Partials          ?      216

Impacted Files	Coverage Δ
internal/configmodels/configmodels.go	0% <0%> (ø)
cmd/occollector/app/builder/pipelines_builder.go	92.72% <100%> (ø)
receiver/jaegerreceiver/factory.go	100% <100%> (ø)
internal/configv2/configv2.go	98.64% <100%> (ø)
receiver/opencensusreceiver/factory.go	82.35% <100%> (ø)
internal/configv2/example_factories.go	55.33% <18.75%> (ø)
receiver/jaegerreceiver/config.go	50% <50%> (ø)
cmd/occollector/app/builder/exporters_builder.go	92.85% <71.42%> (ø)
cmd/occollector/app/collector/collector.go	80.92% <76.47%> (ø)
cmd/occollector/app/builder/receivers_builder.go	85.18% <85.18%> (ø)

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[tigrannajaryan]

@pjanotti all fixed, please review again.