aws-iam: Add description to AccessKey

### Describe the feature

Add the ability to setup accessKey description

### Use Case

In our stack we generate the accessKey for an IAM user and we would like to add a description of why that access key has been generated in the access key description, we already did this manually.

### Proposed Solution

```java
final AccessKey key = AccessKey.Builder
.create(this, accessKey)
.description("Key used to access xxx")
.user(user)
.build();
```

method **description** does not exists.

### Other Information

```xml
2.102.0
```

```xml

software.amazon.awscdk
aws-cdk-lib
${aws.sdk.version}

```

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### CDK version used

2.102.0 (build 2abc59a)

### Environment details (OS name and version, etc.)

mac os x

Start from the AccessKey.Builder API shown in the issue and trace how access keys are configured for an IAM user. Add support for the requested description value and verify that the generated access key includes it; the payload does not name a specific file or test to run.

Written by the indexing model from the issue text.