### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Currently the VTL template for `request_templates` is not processed properly:

```
#set( $body = $input.json("$") )

#macro( loop $map )
{
    #foreach($key in $map.keySet())
        #set( $k = $util.escapeJavaScript($key) )
        #set( $v = $util.escapeJavaScript($map.get($key)).replaceAll("\\'", "'") )
        "$k": "$v"
        #if( $foreach.hasNext ) , #end
    #end
}
#end

{
    "enhancedAuthContext": #loop($context.authorizer),

    "headers": #loop($input.params().header),

    "query": #loop($input.params().querystring),

    "path": #loop($input.params().path),

    "identity": #loop($context.identity),

    "stageVariables": #loop($stageVariables),
}
EOF
}
```

results in,

```
'

{
    "enhancedAuthContext": {
    }
,

    "headers": {
    }
,

    "query": {
    }
,

    "path": {
    }
,

    "identity": {
    }
,

    "stageVariables": {
    }
,
}
'
```

### Expected Behavior

The template should be rendered and have the JSON properties.

### How are you starting LocalStack?

Custom (please describe below)

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    docker run localstack/localstack

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

    awslocal s3 mb s3://mybucket


### Environment

```markdown
- OS: MacOS
- LocalStack: 0.14
```


### Anything else?

This example can be used to validate.
https://github.com/localstack/localstack-terraform-samples/tree/master/apigateway-lambda-velocity
env["AWS_REGION"] = region
def dynamodb_table_exists(table_name, client=None):
    client = client or connect_to_service("dynamodb")
    paginator = client.get_paginator("list_tables")
    pages = paginator.paginate(PaginationConfig={"PageSize": 100})
    for page in pages:
        table_names = page["TableNames"]
        if to_str(table_name) in table_names:
            return True
    return False
def sqs_queue_url_for_arn(queue_arn):
    if "://" in queue_arn:
        return queue_arn
    if queue_arn in SQS_ARN_TO_URL_CACHE:
        return SQS_ARN_TO_URL_CACHE[queue_arn]
    try:
        arn = parse_arn(queue_arn)
        region_name = arn["region"]
        queue_name = arn["resource"]
    except InvalidArnException:
        region_name = None
        queue_name = queue_arn
    sqs_client = connect_to_service("sqs", region_name=region_name)
    result = sqs_client.get_queue_url(QueueName=queue_name)["QueueUrl"]
    SQS_ARN_TO_URL_CACHE[queue_arn] = result
    return result
def get_sqs_queue_url(queue_arn: str) -> str: