[DOCS-8533] New data retention page

[rtrieu]

What does this PR do? What is the motivation?

• Hides old data retention page under Developer Guides
• Adds new one to Data Security

Merge instructions

• [ ] Please merge after reviewing

Additional notes

More details in DOCS-8533.

[github-actions[bot]]

Preview links (active after the build_preview check completes)

New or renamed files

• https://docs-staging.datadoghq.com/rtrieu/docs-8533-new-data-retention-page/data_security/data_retention_periods
• https://docs-staging.datadoghq.com/rtrieu/docs-8533-new-data-retention-page/developers/guide/data-collection-resolution

Removed or renamed files (these should redirect)

• https://docs-staging.datadoghq.com/rtrieu/docs-8533-new-data-retention-page/developers/guide/data-collection-resolution-retention

Modified Files

• https://docs-staging.datadoghq.com/rtrieu/docs-8533-new-data-retention-page/account_management/audit_trail/
• https://docs-staging.datadoghq.com/rtrieu/docs-8533-new-data-retention-page/developers/guide/

[rtrieu]

Closing in favor of https://github.com/DataDog/documentation/pull/26762