[7.12] processor/otel: extend support for OpenTelemetry semantic conventions (#4711)

[axw]

Backports the following commits to 7.12:

• processor/otel: extend support for OpenTelemetry semantic conventions (processor/otel: extend support for OpenTelemetry semantic conventions #4711)

[codecov-io]

Codecov Report

Merging #4818 (419b54c) into 7.12 (05f5a8a) will increase coverage by 0.18%.
The diff coverage is 92.79%.

@@            Coverage Diff             @@
##             7.12    #4818      +/-   ##
==========================================
+ Coverage   76.24%   76.43%   +0.18%     
==========================================
  Files         163      164       +1     
  Lines        9898    10022     +124     
==========================================
+ Hits         7547     7660     +113     
- Misses       2351     2362      +11     

Impacted Files	Coverage Δ
model/context.go	75.96% <0.00%> (-1.49%)	⬇️
processor/otel/builder.go	89.47% <89.47%> (ø)
processor/otel/consumer.go	94.87% <95.42%> (+0.06%)	⬆️
model/modeldecoder/rumv3/decoder.go	95.95% <100.00%> (ø)
model/modeldecoder/v2/decoder.go	97.96% <100.00%> (ø)
processor/otel/metadata.go	60.29% <100.00%> (+6.56%)	⬆️
kibana/connecting_client.go	64.91% <0.00%> (-5.27%)	⬇️
x-pack/apm-server/sampling/processor.go	78.63% <0.00%> (-0.91%)	⬇️

[apmmachine]

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Build stats

• Build Cause: Pull request #4818 opened

• Start Time: 2021-02-19T02:35:32.724+0000

• Duration: 48 min 29 sec

• Commit: 419b54c

Test stats 🧪

Test	Results
Failed	0
Passed	4466
Skipped	126
Total	4592

Trends 🧪

Steps errors

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Compress

• Took 0 min 0 sec . View more details on here
• Description: tar --exclude=coverage-files.tgz -czf coverage-files.tgz coverage

Compress

• Took 0 min 0 sec . View more details on here
• Description: tar --exclude=system-tests-linux-files.tgz -czf system-tests-linux-files.tgz system-tests

Test Sync

• Took 3 min 26 sec . View more details on here
• Description: ./.ci/scripts/sync.sh