[DOCS-9410] Update Cloud SIEM Detection Rules docs

[maycmlee]

What does this PR do? What is the motivation?

• Renames "Log Detection Rules" to "Detection Rules".
• Moves "Signal Correlation Rules" under "Detection Rules".
• Adds aliases.
• Updates old links.

DOCS-9410

Merge instructions

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/merge

Additional notes

[github-actions]

Preview links (active after the build_preview check completes)

New or renamed files

• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/cloud_siem/detection_rules/

Renamed files

• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/cloud_siem/detection_rules/signal_correlation_rules

Modified Files

• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/developers/integrations/create-a-cloud-siem-detection-rule
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/getting_started/cloud_siem/
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/integrations/guide/amazon-eks-audit-logs
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/cloud_siem/content_packs
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/cloud_siem/guide/automate-the-remediation-of-detected-threats
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/cloud_siem/guide/aws-config-guide-for-cloud-siem
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/cloud_siem/guide/azure-config-guide-for-cloud-siem
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/cloud_siem/guide/google-cloud-config-guide-for-cloud-siem
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/detection_rules/
• https://docs-staging.datadoghq.com/may/new-detection-rules-ui/security/threats/workload_security_rules/custom_rules