### 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
if resources is None:
        apigateway = connect_to_service(service_name="apigateway")
        resources = apigateway.get_resources(restApiId=api_id, limit=100)
    if not isinstance(path, list):
        path = path.split("/")
    if not path:
        return parent
    for resource in resources:
        if resource["pathPart"] == path[0] and (not parent or parent["id"] == resource["parentId"]):
            return get_apigateway_resource_for_path(
                api_id, path[1:], parent=resource, resources=resources
            )
    return None
def get_apigateway_path_for_resource(
    api_id, resource_id, path_suffix="", resources=None, region_name=None
):
    if resources is None:
        apigateway = connect_to_service(service_name="apigateway", region_name=region_name)
        resources = apigateway.get_resources(restApiId=api_id, limit=100)["items"]
    target_resource = list(filter(lambda res: res["id"] == resource_id, resources))[0]
    path_part = target_resource.get("pathPart", "")
    if path_suffix:
        if path_part:
            path_suffix = "%s/%s" % (path_part, path_suffix)
    else:
        path_suffix = path_part
    parent_id = target_resource.get("parentId")
    if not parent_id:
        return "/%s" % path_suffix
    return get_apigateway_path_for_resource(