Introducing template variable saved views for dashboards

Datadog's Terraform provider v4.0.0 introduces significant improvements including support for managing Datadog Synthetics tests, enhanced monitoring resource coverage (like SLOs and dashboards), and a streamlined user experience. This release focuses on expanding infrastructure-as-code capabilities within Datadog, allowing users to define and manage more of their observability configuration through Terraform. It also includes important breaking changes, so users are encouraged to review the migration guide before upgrading.