feat(DataSync): Deploy DataSync agent on Amazon EC2 L2 construct

### Describe the feature

It would be nice to have some L2 constructs for DataSync. Specially for creating the DataSync agent on EC2 instance.

### Use Case

Currently only have L1 construct to create DataSync agent which requires the Activation Key. The situation is when the Agent is deployed in the EC2 instance which is part of the CDK deployment, we will need to make the HTTP request to get the ActivationKey, then use it to create the DataSync Agent.

### Proposed Solution

Currently the solution is using custom resource to make this possible in a single CDK deployment. Specifically the Lambda function will make the HTTP call to get the Activation Key and send back to CloudFormation to continue create DataSync Agent resource.
This will be nice to have this abstract in the L2 construct.

### Other Information

_No response_

### Acknowledgements

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

### CDK version used

2.118

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

MacOs

Start by reviewing the existing L1 DataSync agent construct and the proposed custom-resource Lambda flow for obtaining the Activation Key from an EC2-hosted agent. Define the L2 construct boundary and verify that its behavior supports creating the EC2 agent and DataSync resource in one CDK deployment; done should include appropriate construct coverage.

Written by the indexing model from the issue text.