### 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
global CACHE_S3_HOSTNAME_DNS_STATUS
    if CACHE_S3_HOSTNAME_DNS_STATUS is None:
        try:
            assert socket.gethostbyname(S3_VIRTUAL_HOSTNAME)
            CACHE_S3_HOSTNAME_DNS_STATUS = True
        except socket.error:
            CACHE_S3_HOSTNAME_DNS_STATUS = False
    if CACHE_S3_HOSTNAME_DNS_STATUS:
        return S3_VIRTUAL_HOSTNAME
    return LOCALHOST
def render_velocity_template(*args, **kwargs):
    return templating.render_velocity_template(*args, **kwargs)
def generate_presigned_url(*args, **kwargs):
    endpoint_url = kwargs.pop("endpoint_url", None)
    s3_client = connect_to_service(
        "s3",
        endpoint_url=endpoint_url,
        cache=False,
        
        aws_access_key_id=TEST_AWS_ACCESS_KEY_ID,
        aws_secret_access_key=TEST_AWS_SECRET_ACCESS_KEY,
    )
    return s3_client.generate_presigned_url(*args, **kwargs)
def check_valid_region(headers):