Lightweight version on Minimal API in Annotations - Single Handler for multiple Requests

### Describe the feature

Today the annotations project support multiple handlers, however this means the same lambda needs to be deployed multiple times, once for each handler.

### Use Case

Whilst the Minimal API provides a single handler to serves multiple requests, in many cases this is overkill.

If no conventional middleware support is required (just a DI container), it would be great to add a level of indirection into Annotations such that it can meet the same use cases in a more compact footprint.

A suite of related API's can then scale up/out based on need than at the more granular hander level. This also simplifies the deployment model.

### Proposed Solution

The indirection could be based on the raw APIGatewayProxyRequest/APIGatewayProxyResponse that can be achieved today. However this leads a lot for manual implementation than leverage the components that already exist in the library with the attributes [FromBody], [FromServices] etc.

```C#
[LambdaFunction]
public async Task FunctionHandlerAsync(
APIGatewayProxyRequest request,
[FromServices] IServiceProvider provider,
[FromServices] ILogger logger,
ILambdaContext context)
{
// with a switch on the request path to an implementation and delegate to a sub handler.
// That in turn can deserialize the body, and
// use the IServiceProvider to pull needed services.
// It would also have to deserialize the response

}
```
Perhaps there is a new attribute called (say) `[SubLambdaFunction]` that behaves similarly to the current ` [LambdaFunction]` that causes the underlying method above to be source generated that in runs invokes each [SubLambdaFunction] and handles the response processing?

### Other Information

The `serverless.template` would still generate for the specific routes of each request as deployed to the API G/W mapping them to the same **_single_** Lambda Handler than one for each.

### Acknowledgements

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

### AWS .NET SDK and/or Package version used

Amazon.Lambda.Annotations

### Targeted .NET Platform

.Net 6/7/8

### Operating System and version

N/A