Azure container docker image

[narph]

What does this PR do?

Why is it important?

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.

Related issues

• Relates Update Elastic Agent docker image for azure containers runtime #82

[mergify]

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

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

NOTE: backport-skip has been added to this pull request.

[elasticmachine]

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Build stats

• Start Time: 2022-06-01T09:30:25.665+0000

• Duration: 36 min 1 sec

Test stats 🧪

Test	Results
Failed	0
Passed	5973
Skipped	23
Total	5996

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[elasticmachine]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	97.183% (69/71)	👍
Files	68.182% (150/220)	👍
Classes	67.955% (299/440)	👍
Methods	51.668% (821/1589)	👍
Lines	38.054% (8803/23133)	👎 -0.056
Conditionals	100.0% (0/0)	💚

[jsoriano]

We may want to remove all this conditional logic depending on the user of the image, and remove the parts run only for user root.
This comes from the template used by Beats, where there were beats images run with user root (auditbeat and packetbeat IIRC). But all elastic-agent images use the elastic-agent user, find the definition here.
This would simplify this template.

[jsoriano]

Does this change anything when tini is executed as PID 1?

Notice that this breaks compatibility with Linux < 3.4. But I guess we don't support any distribution with such old versions, so I guess this is fine.

[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 azure-container upstream/azure-container
git merge upstream/main
git push upstream azure-container

[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 azure-container upstream/azure-container
git merge upstream/main
git push upstream azure-container

[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 azure-container upstream/azure-container
git merge upstream/main
git push upstream azure-container