Add support to ingest cloud_metadata for DBM host linking

[jmeunier28]

What does this PR do?

Adds three new fields associated with the database-monitoring product in order to help support the new (beta) DB List feature. Ingesting this extra cloud related metadata will allow for us to link managed cloud resource metrics emitted by Datadog cloud crawlers to database-monitoring reported hosts.

Follow on PR to #11987

Motivation

Additional Notes

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached

[codecov]

Codecov Report

Merging #11988 (826cb5d) into master (194b7dd) will increase coverage by 0.07%.
The diff coverage is 100.00%.

Flag	Coverage Δ
mysql	88.91% <100.00%> (+1.40%)	⬆️

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[github-actions]

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