Motivation

Werkzeug has clever utilities such as Submount which allows you to streamline the creation of routers:

url_map = Map([
    Rule('/', endpoint='index'),
    Submount('/blog', [
        Rule('/', endpoint='blog/index'),
        Rule('/entry/<entry_slug>', endpoint='blog/show')
    ])
])

Our @route, @resource, or endpoint concepts have not been compatible with these, because the werkzeug Rule objects are created within Router.add, instead of an encapsulating RuleFactory, which is werkzeug's mechanism of building higher-level routing utilities.

This PR moves all the code that generates Rule objects out of Router.add, and instead encapsulates them into RuleFactory classes. This makes them naturally compatible with werkzeug.

For instance, now you can do something like:

@route("/v1/hello", methods=["GET"])
def hello(request: Request, _args):
    return "hello"

@route("/v1/world", methods=["GET"])
def world(request: Request, _args):
    return "world"

def main():
    router = Router()

    api = RuleAdapter([
        hello,
        world,
    ])
    
    router.add([
        WithHost("myextension.localhost.localstack.cloud:4566", [api]),
        Submount("/_ext/myextension", [api]),
    ])

Where you'll be able to call:

• localhost:4566/_ext/myextension/v1/hello
• myextension.localhost.localstack.cloud:4566/v1/hello

This is going to be very useful to implement higher-level patterns like in extensions. For example, for the openai mock extension localstack/localstack-extensions#36, there are several routes that all have hardcoded routes prefixed with /v1/.... We wouldn't want to expose this via localhost.localstack.cloud:4566/v1/... because of potential collisions, but would be ok through openai.localhost... or localhost.localstack.cloud:4566/openai-mock/v1/....
The utilities of this PR allows you to easily do that with a combination of WithHost and Submount, as in the example above.

Changes

• the logic to create werkzeug Rule objects from endpoints and other localstack concepts is now in a RuleAdapter class that is compatible with werkzeug's RuleFactory
• Removed deprecated methods from Router and refactored existing code accordingly