### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When creating base-path-mappings on an API Gateway, there is a special `(none)` path when you don't specify a path during creation. Localstack stores this as `basePath: "(none)"` internally.
When you query to get the base paths, the URLs are escaped by the client (verified in both awscli and terraform) so the basePath is sent as `%28none%29` in the url.
Localstack doesn't appear to be decoding urls and when you attempt to get-base-path-mapping it fails in a string comparison of `(none)` to `%28none%29`.

```shell
> aws --endpoint-url=http://localhost:4566 apigateway get-base-path-mapping --domain-name example.com --base-path "(none)"

An error occurred (NotFoundException) when calling the GetBasePathMapping operation: Base path mapping not found: %28none%29
```

### Expected Behavior

When you attempt to get-base-path-mappings after creating one with the (none) path, it succeeds and returns the mapping.

```
> aws --endpoint-url=http://localhost:4566 apigateway get-base-path-mapping --domain-name example.com --base-path "(none)"

{
    "basePath": "(none)",
    "restApiId": "uyy4c3dsho",
    "stage": "dev"
}
```


### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

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

    make start

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

    awslocal apigateway create-rest-api --name "testgw"
    awslocal apigateway create-base-path-mapping --domain-name example.com --rest-api-id <from output above> --stage dev
    awslocal apigateway get-base-path-mapping --domain-name example.com --base-path "(none)"



### Environment

```markdown
- OS: fedora 34
- LocalStack: latest
```


### Anything else?

https://docs.aws.amazon.com/apigateway/api-reference/link-relation/basepathmapping-by-base-path/
{"data": '{"foo": "bar1"}'},
                {"data": '{"foo": "bar2"}'},
                {"data": '{"foo": "bar3"}'},
            ]
        }
        url = gateway_request_url(
            api_id=result["id"],
            stage_name=self.TEST_STAGE_NAME,
            path=self.API_PATH_DATA_INBOUND,
        )
        
        result = requests.get(url)
        result = json.loads(to_str(result.content))
        self.assertIn("StreamNames", result)
        
        result = requests.post(url, data=json.dumps(test_data))
        result = json.loads(to_str(result.content))
        self.assertEqual(0, result["FailedRecordCount"])
        self.assertEqual(len(test_data["records"]), len(result["Records"]))
        
        kinesis = aws_stack.connect_to_service("kinesis")
        kinesis.delete_stream(StreamName=self.TEST_STREAM_KINESIS_API_GW)
    def test_api_gateway_sqs_integration_with_event_source(self):
        
        queue_name = "queue-%s" % short_uid()
        queue_url = aws_stack.create_sqs_queue(queue_name)["QueueUrl"]
        
        result = connect_api_gateway_to_sqs(
            "test_gateway4",
            stage_name=self.TEST_STAGE_NAME,