### 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/
search_match = re.search(PATH_REGEX_RESPONSES, path)
    api_id = search_match.group(1)
    response_type = (search_match.group(2) or "").lstrip("/")
    if method == "GET":
        if response_type:
            return get_gateway_response(api_id, response_type)
        return get_gateway_responses(api_id)
    if method == "PUT":
        return put_gateway_response(api_id, response_type, data)
    if method == "PATCH":
        return update_gateway_response(api_id, response_type, data)
    if method == "DELETE":
        return delete_gateway_response(api_id, response_type)
    return make_error_response(
        "Not implemented for API Gateway gateway responses: %s" % method, code=404
    )
def to_authorizer_response_json(api_id, data):
    return to_response_json("authorizer", data, api_id=api_id)
def to_validator_response_json(api_id, data):
    return to_response_json("validator", data, api_id=api_id)
def to_documentation_part_response_json(api_id, data):