Hi

I have issues creating sns subscriptions through Cloudformation. If I attempt to include a `AWS::SNS::Subscription` resource in a Cloudformation template and run `create-stack` then I get a 500 Internal Server error. The full template:

```
AWSTemplateFormatVersion: '2010-09-09'
Description: 'Test'
Resources:
  MySnsTopic:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: MySnsTopic
  MySnsTopicSubscription:
    Type: AWS::SNS::Subscription
    Properties:
      Protocol: sqs
      TopicArn: !Ref MySnsTopic
      Endpoint: !GetAtt
        - MySqsQueue
        - QueueArn
  MySqsQueue:
    Type: AWS::SQS::Queue
    Properties:
      QueueName: MySqsQueue
```

If I replace the references with hard-coded arns like this:

```
TopicArn: arn:aws:sns:eu-west-2:123456789012:MySnsTopic
Endpoint: arn:aws:sqs:elasticmq:000000000000:MySqsQueue
```

Then I get no errors but I get a warning:

`No moto Cloudformation support for AWS::SNS::Subscription`.

I can get around this issue by creating the subscription when creating the topic but the issue there is that I cannot add any attributes and in my case I need `RawMessageDelivery` set to true. So my questions are:

1. Is there no support to create `AWS::SNS::Subscription` resources through Cloudformation or am I doing something wrong?
2. If support is not there can I request it as a new feature?
3. Any suggestions on how I can work around this? I know I could do this through a script at startup but would like to not have any additional script steps other than deploying the Cloudformation stack.

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res_type = resource.get('Type', '')
    parts = res_type.split('::')
    if len(parts) == 1:
        return None
    if res_type.endswith('Cognito::UserPool'):
        return 'cognito-idp'
    if parts[-2] == 'Cognito':
        
        return 'cognito-idp'
    return parts[1].lower()
def get_resource_name(resource):
    res_type = get_resource_type(resource)
    properties = resource.get('Properties') or {}
    name = properties.get('Name')
    if name:
        return name
    
    if res_type == 'S3::Bucket':
        name = properties.get('BucketName')
    elif res_type == 'SQS::Queue':
        name = properties.get('QueueName')
    elif res_type == 'Cognito::UserPool':
        name = properties.get('PoolName')
    else:
        LOG.warning('Unable to extract name for resource type "%s"' % res_type)
    return name
def get_client(resource):