[extension/encoding] support skywalkingencoding extension

[JaredTan95]

Description

The kafkareceiver supports jaeger and zipkin protocol traces, and can also receive skywalkng traces via skywalkingreceiver.

From the practical use of skywalking, we often use kafka to host large-scale traces data. However, kafka receiver does not support skywalking encoding currently.

with this PR, we can fectch skywalking traces and parse it into otlp traces:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
  kafka:
    encoding: skywalking_encoding
    topic: skywalking-segments
    brokers:
      - "localhost:9092"
    resolve_canonical_bootstrap_servers_only: true
    client_id: otel-collector
    group_id: otel-collector
    metadata:
      retry:
        max: 10
        backoff: 5s

exporters:
  debug:

processors:
  batch:

extensions:
  health_check:
  pprof:
    endpoint: :1888
  zpages:
    endpoint: :55679
  skywalking_encoding:

service:
  extensions: [pprof, zpages, skywalking_encoding, health_check]
  pipelines:
    traces:
      receivers: [kafka]
      processors: [batch]
      exporters: [debug]

Link to tracking issue

Fixes #28693

Testing

Documentation

[crobert-1]

Do you know how to fix the check-owners failed lint?

logs show that I need to do some changes:

- extension/encoding/                               @open-telemetry/collector-contrib-approvers @atoulme @dao-jun @dmitryax @MovieStoreGuy @VihasMakwana
+ extension/encoding/                               @open-telemetry/collector-contrib-approvers @atoulme @dao-jun @dmitryax @MovieStoreGuy @VihasMakwana @JaredTan95 

in .github/CODEOWNERS file, but @atoulme told me do it in separate PR, so, I'm confused~

This is the current action failure output:

Generated code is out of date, please apply this diff and commit the changes in this PR.
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 004df01..3baf60[9](https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/12665959423/job/35296498228?pr=36968#step:5:10) 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -95,6 +95,7 @@ extension/encoding/avrologencodingextension/      @open-telemetry/collector-cont
 extension/encoding/jaegerencodingextension/       @open-telemetry/collector-contrib-approvers @MovieStoreGuy @atoulme
 extension/encoding/jsonlogencodingextension/      @open-telemetry/collector-contrib-approvers @VihasMakwana @atoulme
 extension/encoding/otlpencodingextension/         @open-telemetry/collector-contrib-approvers @dao-jun @VihasMakwana
+extension/encoding/skywalkingencodingextension/   @open-telemetry/collector-contrib-approvers @JaredTan95
 extension/encoding/textencodingextension/         @open-telemetry/collector-contrib-approvers @MovieStoreGuy @atoulme
 extension/encoding/zipkinencodingextension/       @open-telemetry/collector-contrib-approvers @MovieStoreGuy @dao-jun
 extension/googleclientauthextension/              @open-telemetry/collector-contrib-approvers @dashpole @aabmass @jsuereth @punya @psx95
Error: Process completed with exit code 1.

It's simply missing a line for the new extension you're adding, it's no longer complaining about the extension/encoding entry 👍

[codecov]

Codecov Report

Attention: Patch coverage is 73.07692% with 7 lines in your changes missing coverage. Please review.

Project coverage is 79.59%. Comparing base (12551d3) to head (0849205).

Files with missing lines	Patch %	Lines
.../encoding/skywalkingencodingextension/extension.go	33.33%	4 Missing ⚠️
...encoding/skywalkingencodingextension/skywalking.go	57.14%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #36968      +/-   ##
==========================================
- Coverage   79.59%   79.59%   -0.01%     
==========================================
  Files        2252     2255       +3     
  Lines      211914   211940      +26     
==========================================
+ Hits       168682   168699      +17     
- Misses      37562    37571       +9     
  Partials     5670     5670              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.