CDK: Region validation

### Describe the feature

If a region is set for a Stack, CDK should validate if the synthesized constructs match the actual supported resources of that region. As each region supports different services (or even different features) a shift-left of the validation helps developer to get early feedback if their solution will be deployable on that region.

### Use Case

Whenever a new Region launches I want to verify if my code is deployable to that region. An actual deployment is not helpful as it could have side effects and fails usually on the first missing service. It does not give me an overview of which services I have in my stack that are not or only partial supported. Failing during `cd synth` helps to get an early feedback and to check that regularly (as available services and their features of a region changes over time).

Another use-case is related to the launch of the European Sovereign Cloud in 2025. As preparation it is useful to be able to build solutions that will be compatible with the [initial supported services](https://aws.amazon.com/blogs/security/announcing-initial-services-available-in-the-aws-european-sovereign-cloud-backed-by-the-full-power-of-aws/).

### Proposed Solution

Use the same sources as the [Region Comparison Tool](https://region-comparison.aws.com/)

### Other Information

_No response_

### Acknowledgements

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

### CDK version used

v2 (latest)

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

OSX 14.5

Start by reviewing how a region is set on a CDK Stack and how `cd synth` processes synthesized constructs. Compare the available region-support data with the Region Comparison Tool linked in the issue. Done means synthesis identifies services or features unsupported, or only partially supported, in the selected region without requiring deployment.

Written by the indexing model from the issue text.