Adding AWS SDK Mock to go-spectest/aws

[nao1215]

Is your feature request related to a problem? Please describe.

We are implementing mocks for the official AWS package (SDK) in go-spectest/aws. The package was severely broken at the time of forking, and there was also an issue with the limited number of supported AWS resources.

Therefore, we believe it would be best to start fresh by adding AWS SDK mocks anew. With over 100 types of AWS resources, manually adding mocks would be daunting. We are considering adopting a method to automatically generate mocks from the interfaces exposed by the AWS SDK.

Additional context

Eventually, go-spectest/aws is planned to be integrated into go-spectest/spectest.