add metricbeat receiver

[leehinman]

What does this PR do?

Adds metricbeat receiver to included otel receivers

Why is it important?

Needed for supporting metric modules.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

None. Only enabled if specified in otel configuration

How to test this PR locally

Unit Test

mage integration:auth
mage integration:single TestOtelMBReceiverE2E

By hand

elastic-agent otel -c otel.yml

with the following for otel.yml

---
receivers:
  metricbeatreceiver:
    metricbeat:
      modules:
        - module: system
          enabled: true
          period: 1s
          processes:
            - '.*'
          metricsets:
            - cpu
    output:
      otelconsumer:
    logging:
      level: info
      selectors:
        - '*'
    queue.mem.flush.timeout: 0s
exporters:
  debug:
    verbosity: detailed
service:
  pipelines:
    logs:
      receivers:
        - metricbeatreceiver
      exporters:
        - debug

Related issues

• Closes Add metricbeat receiver and E2E integration test #6138

Questions to ask yourself

• How are we going to support this in production?
• How are we going to measure its adoption?
• How are we going to debug this?
• What are the metrics I should take care of?
• ...

[mergify]

This pull request does not have a backport label. Could you fix it @leehinman? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-./d./d is the label to automatically backport to the 8./d branch. /d is the digit

[mergify]

backport-v8.x has been added to help with the transition to the new branch 8.x.
If you don't need it please use backport-skip label and remove the backport-8.x label.

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b 6138_metricbeat_receiver upstream/6138_metricbeat_receiver
git merge upstream/main
git push upstream 6138_metricbeat_receiver

[mauri870]

Codewise looks good, I tested locally following the issue description and it works as intended, I can see the metrics in the collector logs.

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube