github: unify PR description and commit message

[efd6]

What does this PR do?

To improve the quality of commit messages in the revision history, indicate that the commit message will be part of the PR review process and integrate the WHAT and WHY questions in the change explanation.

Remove the checklist item for PR title and description as it becomes redundant with this new text.

Why is it important?

Included in the text above.

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.
• I have made my commit title and message explanatory about the purpose and the reason of the change

Author's Checklist

• [ ]

How to test this PR locally

Related issues

Use cases

Screenshots

Logs

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[elasticmachine]

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

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @efd6? 🙏.
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]

💚 Build Succeeded

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Build stats

• Start Time: 2023-08-01T21:53:30.310+0000

• Duration: 9 min 39 sec

❕ Flaky test report

No test was executed to be analysed.

🤖 GitHub comments

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[pierrehilbert]

I would remove this one as we already have "Please explain:" just after.
Otherwise everything is good to me!

[efd6]

I guess this is a matter of style. The text here reflects the text that was previously there, just now on two lines. The thinking that I had with retaining the text as it is was that the first line is the overall goal of the section, while the second is the specific parts that should be addressed. If you still want me to remove it given that, I'm happy to.

[cmacknz]

I don't have a problem with it as it is, but if you can make it shorter people are more likely to read it :p

[efd6]

I agree about that. We need to have reviewers on board to point to this, so the main issue is whether that will happen.