Add `deploy_instance_count` and `deploy_instance_type` to `TrainingPipeline`

Currently, [TrainingPipeline](https://github.com/aws/aws-step-functions-data-science-sdk-python/blob/b45b282592041d3c355f7cef492798bc3bf5415a/src/stepfunctions/template/pipeline/train.py#L95) uses the same instance type and count for both train and deploy.

Different instance types and counts are desirable to address the different profiles for each workload.

从 src/stepfunctions/template/pipeline/train.py 开始，重点查看 issue 中链接的 TrainingPipeline 定义。跟踪当前实例类型和数量如何应用于训练和部署，然后确定分别配置 deploy 值的位置。完成的标准是 TrainingPipeline 接受 deploy_instance_count 和 deploy_instance_type，并独立于训练设置使用它们。

由索引模型根据 Issue 内容生成。