Merge otlp grpc trace and metric exporter into :exporters:otlp:all

[jack-berg]

Related to #4482.

If approved I'd like to do the same otlp http by merging :exporters:otlp-http:trace and :exporters:otlp-http:metrics into a new module called :exporters:otlp-http:all.

[codecov]

Codecov Report

Merging #4494 (ad2dd6b) into main (de824dc) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main    #4494   +/-   ##
=========================================
  Coverage     90.02%   90.02%           
  Complexity     5034     5034           
=========================================
  Files           578      578           
  Lines         15536    15536           
  Branches       1494     1494           
=========================================
  Hits          13987    13987           
  Misses         1089     1089           
  Partials        460      460           

Impacted Files	Coverage Δ
...ter/otlp/metrics/ExportMetricsServiceResponse.java	100.00% <ø> (ø)
...rter/otlp/metrics/MarshalerMetricsServiceGrpc.java	90.47% <ø> (ø)
.../exporter/otlp/metrics/OtlpGrpcMetricExporter.java	81.81% <ø> (ø)
...er/otlp/metrics/OtlpGrpcMetricExporterBuilder.java	94.44% <ø> (ø)
...xporter/otlp/trace/ExportTraceServiceResponse.java	100.00% <ø> (ø)
...exporter/otlp/trace/MarshalerTraceServiceGrpc.java	90.47% <ø> (ø)
...etry/exporter/otlp/trace/OtlpGrpcSpanExporter.java	77.77% <ø> (ø)
...porter/otlp/trace/OtlpGrpcSpanExporterBuilder.java	93.93% <ø> (ø)

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[anuraaga]

This seems reasonable to me, it's a tiny amount of code in each artifact. What do you think of merging the HTTP exporters into this same artifact too?

[jack-berg]

Was planning on doing a separate artifact for the http exporters, but come to think of it, both grpc and the http versions depend on okhttp, and share the same serialization code, so why not?