[AWS::DynamoDB::GlobalTable] - [Enhancement] - Support adding replica regions as a separate resource to leverage Fn::ForEach

### Name of the resource

AWS::DynamoDB::GlobalTable

### Resource name

_No response_

### Description

It would be incredibly helpful if Global Table replicas could be added via a separate resource, instead of defining them on the GlobalTable resource itself. I liken this to the `AWS::EC2::SecurityGroupIngress`, which can be defined separately from `AWS::EC2::SecurityGroup`. This would open up the possibility of defining replica regions using `Fn::ForEach`, as that intrinsic function can iterate over `CommaDelimitedList` parameters.

Consider this example:

```yaml
AWSTemplateFormatVersion: "2010-09-09"
Description: "Core Dynamo"
Transform: 'AWS::LanguageExtensions'

Parameters:
ReplicaRegions:
Type: "CommaDelimitedList"
Description: "Regions to replicate the DynamoDB table to"

Resources:
Table:
Type: "AWS::DynamoDB::GlobalTable"
Properties:
AttributeDefinitions:
- AttributeName: "_key"
AttributeType: "S"
- AttributeName: "_version"
AttributeType: "N"
KeySchema:
- AttributeName: "_key"
KeyType: "HASH"
- AttributeName: "_version"
KeyType: "RANGE"
BillingMode: "PAY_PER_REQUEST"
Fn::ForEach::Replicas:
- Region
- Ref: ReplicaRegions
- "TableReplica&{Region}":
Type: "AWS::DynamoDB::GlobalTableReplica"
Properties:
Table: !Ref Table
Region: !Sub "${Region}"
PointInTimeRecoverySpecification:
PointInTimeRecoveryEnabled: true
```

Alternately, if `Fn::ForEach` could produce arrays, that would replace this request.

### Other Details

_No response_

The issue identifies no repository files or tests; start with the CloudFormation example using AWS::DynamoDB::GlobalTable and Fn::ForEach. Done would mean either a separate replica resource that supports iterating CommaDelimitedList regions or Fn::ForEach support for producing arrays.

Written by the indexing model from the issue text.