Remove last dependencies on beats repo

[kvch]

What does this PR do?

This PR removes the last two package dependencies on the beats repo:

• one small dependency on Metricbeat for parsing URLs
• one bad import from the old agent code

Why is it important?

Elasitc Agent is now free from Beats.

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.

[mergify]

This pull request does not have a backport label. Could you fix it @kvch? 🙏
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: 2022-04-28T11:03:22.251+0000

• Duration: 33 min 37 sec

Test stats 🧪

Test	Results
Failed	0
Passed	3849
Skipped	21
Total	3870

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[narph]

LGTM