### 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/
restApiId=rest_api_id,
            name=_name,
            description=description,
            contentType=content_type,
        )
        self.assertEqual(_name, response["name"])
        self.assertEqual(description, response["description"])
        with self.assertRaises(Exception) as ctx:
            client.create_(
                restApiId=dummy_rest_api_id,
                name=_name,
                description=description,
                contentType=content_type,
            )
        self.assertEqual("NotFoundException", ctx.exception.response["Error"]["Code"])
        self.assertEqual(
            "Invalid Rest API Id specified", ctx.exception.response["Error"]["Message"]
        )
        with self.assertRaises(Exception) as ctx:
            client.create_(
                restApiId=dummy_rest_api_id,
                name="",
                description=description,
                contentType=content_type,
            )
        self.assertEqual("BadRequestException", ctx.exception.response["Error"]["Code"])
        self.assertEqual("No Model Name specified", ctx.exception.response["Error"]["Message"])
        
        client.delete_rest_api(restApiId=rest_api_id)
    def test_get_api_s(self):