[AWS] Add in workspace_settings_v2 resources to replace current databricks_workspace_conf resource

[JDBraun]

In the past, workspace_confs were used: https://github.com/databricks/terraform-databricks-sra/blob/main/aws/customizations/workspace/admin_configuration/admin_configuration.tf, but these were unsupported by the platform and caused downstream issues, so they were moved into the customizations folder

There is now workspace_settings_v2 that is in public preview that covers these settings like export settings: https://docs.databricks.com/api/workspace/enableexportnotebook/patchenableexportnotebook / https://registry.terraform.io/providers/databricks/databricks/latest/docs/resources/workspace_setting_v2

The existing workspace_confs should be ported to the new endpoint and merged back into the main folder