### 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/
return path.lstrip("/").split("/")
def extract_path_params(path, extracted_path):
    tokenized_extracted_path = tokenize_path(extracted_path)
    
    path_params_list = [(i, v) for i, v in enumerate(tokenized_extracted_path) if "{" in v]
    tokenized_path = tokenize_path(path)
    path_params = {}
    for param in path_params_list:
        path_param_name = param[1][1:-1].encode("utf-8")
        path_param_position = param[0]
        if path_param_name.endswith(b"+"):
            path_params[path_param_name] = "/".join(tokenized_path[path_param_position:])
        else:
            path_params[path_param_name] = tokenized_path[path_param_position]
    path_params = common.json_safe(path_params)
    return path_params
def extract_query_string_params(path):
    parsed_path = urlparse.urlparse(path)
    path = parsed_path.path
    parsed_query_string_params = urlparse.parse_qs(parsed_path.query)
    query_string_params = {}
    for query_param_name, query_param_values in parsed_query_string_params.items():
        if len(query_param_values) == 1:
            query_string_params[query_param_name] = query_param_values[0]
        else:
            query_string_params[query_param_name] = query_param_values
    
    path = path.rstrip("/") or "/"
    return [path, query_string_params]
def get_cors_response(headers):