### 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/
response_templates=None,
        is_api_key_required=False,
        integration_type=None,
        integration_responses=None,
    ):
        response_templates = response_templates or {}
        integration_type = integration_type or "AWS_PROXY"
        apigw_client = aws_stack.connect_to_service("apigateway")
        response = apigw_client.create_rest_api(name="my_api", description="this is my api")
        api_id = response["id"]
        resources = apigw_client.get_resources(restApiId=api_id)
        root_resources = [resource for resource in resources["items"] if resource["path"] == "/"]
        root_id = root_resources[0]["id"]
        kwargs = {}
        if integration_type == "AWS_PROXY":
            aws_stack.create_dynamodb_table("MusicCollection", partition_key="id")
            kwargs[
                "uri"
            ] = "arn:aws:apigateway:us-east-1:dynamodb:action/PutItem&Table=MusicCollection"
        if not integration_responses:
            integration_responses = [{"httpMethod": "PUT", "statusCode": "200"}]
        for resp_details in integration_responses:
            apigw_client.put_method(