[google_scc] Add support for Security Command Center API v2

[brijesh-elastic]

Proposed commit message

google_scc: Add support for Security Command Center API v2

Some fields inside "google_scc.finding.resource" are moved into "google_scc.finding.resource.gcp_metadata" as per v2 API schema.
This change allows to choose between v1 and v2 (recommended) APIs to fetch findings.
Location-based findings can be fetched to support Security Command Center data residency feature.
Field "google_scc.finding.vulnerability.cve.cvssv3.base_score" data type is updated to "double" to better suit data.

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.
• I have verified that any added dashboard complies with Kibana's Dashboard good practices

How to test this PR locally

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

elastic-package test

[elasticmachine]

Pinging @elastic/security-service-integrations (Team:Security-Service Integrations)

[elastic-vault-github-plugin-prod]

🚀 Benchmarks report

To see the full report comment with /test benchmark fullreport

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 00031e4

cc @brijesh-elastic

[elastic-sonarqube]

Quality Gate failed

Failed conditions
62.7% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube