Remove libbeat/common/transport/httpcommon and libbeat/common/transport/tlscommon

[kvch]

What does this PR do?

This PR removes the following packages:

• github.com/elastic/beats/v7/libbeat/common/transport/httpcommon
• github.com/elastic/beats/v7/libbeat/common/transport/tlscommon

I am not fixing linter issues.

Why is it important?

Avoid maintaining the same code in two places.

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.

[elasticmachine]

💚 Build Succeeded

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Build stats

• Start Time: 2022-05-16T14:03:09.708+0000

• Duration: 142 min 53 sec

Test stats 🧪

Test	Results
Failed	0
Passed	24785
Skipped	2146
Total	26931

💚 Flaky test report

Tests succeeded.

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[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 move-transport upstream/move-transport
git merge upstream/main
git push upstream move-transport

[elasticmachine]

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

[rdner]

Still waiting for the build to finish but all changes make sense to me.