[GCP] set event.module and event.dataset

[mtojek]

What does this PR do?

This PR adds event.module and event.dataset to the integration.

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.
• If I'm introducing a new feature, I have modified the Kibana version constraint in my package's manifest.yml file to point to the latest Elastic stack release (e.g. ^7.13.0).

[elasticmachine]

Pinging @elastic/integrations (Team:Integrations)

[elasticmachine]

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Build stats

• Build Cause: Pull request #1240 opened

• Start Time: 2021-06-29T12:37:36.100+0000

• Duration: 20 min 17 sec

• Commit: 30d2362

Test stats 🧪

Test	Results
Failed	0
Passed	23
Skipped	0
Total	23

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