Duckpy

- Basic typing hint support: Results are now a list of ResultDict objects.
- Update dependencies.

- Exclude ads from search results.

- Replace urllib3 and aiohttp with httpx.
- Add HTTP/2 support.
- Add initial typing support.
- Parse DuckDuckGo page inside an executor in asyncio mode.
- Deprecate the `random_ua` parameter in favor of the `default_user_agents` parameter.
- Deprecate the `duckpy.aio` package. Please use `duckpy.AsyncClient` instead.

Bugfixes and code changes.

- Implement the exact_match parameter (add quotation marks in search)
- Add missing proxy support to asyncio variant

Initial asyncio variant