filebeat/module/nginx/ingress_controller: Add unix socket log parsing

[leweafan]

What does this PR do?

Adds unix socket log parsing for nginx ingress_controller

Why is it important?

Nginx ingress_controller pipeline can not parse kubernetes nginx ingress controller logs if unix socket used.

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.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Author's Checklist

• [ ]

How to test this PR locally

Related issues

• Closes Nginx ingress_controller pipeline can not parse domain socket #30702

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[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @leweafan? 🙏.
For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v8./d.0 is the label to automatically backport to the 8./d branch. /d is the digit

[elasticmachine]

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• Start Time: 2023-03-08T07:13:11.589+0000

• Duration: 71 min 50 sec

Test stats 🧪

Test	Results
Failed	0
Passed	7567
Skipped	746
Total	8313

💚 Flaky test report

Tests succeeded.

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[tetianakravchenko]

Thank you for contribution!

[tetianakravchenko]

@gsantoro could you please review as well? do you think it is smth that we should backport to https://github.com/elastic/integrations/tree/main/packages/nginx_ingress_controller?

[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 main upstream/main
git merge upstream/main
git push upstream main