Refactored `databricks_zones` and `databricks_spark_versions` data sources to Go SDK

[nkvuong]

Changes

• Refactored databricks_zones to Go SDK
• Refactored databricks_spark_versions to Go SDK. This refactoring require one additional change to resource.go:
  • Add new method WorkspaceDataWithCustomizeFunc to allow customization of the data source schema
• Removed Spark versions related methods, as these have now moved to Go SDK. This requires migrating the function LatestSparkVersionOrDefault to a Go SDK method, which requires changing existing structs in Terraform provider to equivalent in Go SDK (clusters.SparkVersionsList to compute.GetSparkVersionsResponse, etc.)

Tests

• [x] make test run locally
• [x] covered with integration tests in internal/acceptance
• [ ] relevant acceptance tests are passing
• [x] using Go SDK