Support X-Ray locally

According to the README:
> The component does _not_ support X-ray and other Lambda integrations locally.

So...how hard would it be to add this support for local X-Ray integration?

I think the primary use case for this would be to allow functions built with the SAM CLI that utilize X-Ray (e.g., with `AWSXRay.captureAWSv3Client`) to run locally. Not having this integration requires annoying hacks to import or not import the X-Ray SDK based on where the function is deployed. For more info, and to add some support to my request, please have a look at [this issue](https://github.com/aws/aws-sam-cli/issues/217) in the SAM CLI repo, where people have been ranting about this feature since 2017. 😅

先从 README 中关于本地 X-Ray 集成和其他 Lambda 集成不受支持的说明开始，然后阅读链接的 SAM CLI issue #217，了解之前的背景和所要求的行为。定义本地 X-Ray 集成的范围，并使用采用 AWSXRay.captureAWSv3Client 的 SAM CLI 函数对其进行验证；完成的标准是该函数无需条件式导入 X-Ray SDK 即可在本地运行。

由索引模型根据 Issue 内容生成。