### 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/
import json
import logging
import re
from typing import Any, Dict, List, Tuple
from botocore.utils import InvalidArnException
from jsonpatch import apply_patch
from jsonpointer import JsonPointerException
from moto.apigateway import models as apigateway_models
from moto.apigateway.utils import create_id as create_resource_id
from requests.models import Response
from six.moves.urllib import parse as urlparse
from localstack import config
from localstack.constants import APPLICATION_JSON, PATH_USER_REQUEST, TEST_AWS_ACCOUNT_ID
from localstack.services.generic_proxy import RegionBackend
from localstack.utils import common
from localstack.utils.aws import aws_stack
from localstack.utils.aws.aws_responses import requests_error_response_json, requests_response
from localstack.utils.aws.aws_stack import parse_arn
LOG = logging.getLogger(__name__)
PATH_REGEX_MAIN = r"^/restapis/([A-Za-z0-9_\-]+)/[a-z]+(\?.*)?"
PATH_REGEX_SUB = r"^/restapis/([A-Za-z0-9_\-]+)/[a-z]+/([A-Za-z0-9_\-]+)/.*"
PATH_REGEX_SUB = r"^/restapis/([A-Za-z0-9_\-]+)/[a-z]+/([A-Za-z0-9_\-]+)/.*"
PATH_REGEX_AUTHORIZERS = r"^/restapis/([A-Za-z0-9_\-]+)/authorizers/?([^?/]+)?(\?.*)?"
PATH_REGEX_VALIDATORS = r"^/restapis/([A-Za-z0-9_\-]+)/requestvalidators/?([^?/]+)?(\?.*)?"