[carbon_black_cloud] Capture user domain from hostname and username field

[darshan-elastic]

What does this PR do?

• Added grok pattern on hostaname and username that extract the domain

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

How to test this PR locally

• Clone integrations repo.
• Install elastic-package locally.
• Start elastic stack using elastic-package.
• Move to integrations/packages/carbon_black_cloud directory.
• Run the following command to run tests.
  elastic-package test

Related issues

• Suggestion Link: [carbon_black_cloud] Add Carbon Black Cloud package. #2760 (comment)

Screenshots

[elasticmachine]

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Build stats

• Start Time: 2022-04-14T20:04:22.271+0000

• Duration: 15 min 30 sec

Test stats 🧪

Test	Results
Failed	0
Passed	97
Skipped	0
Total	97

🤖 GitHub comments

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[elasticmachine]

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

[andrewkroh]

/test