Asyncio-taskpool

Add full typing support and improve code quality
Features

- Add `py.typed` marker for static type checkers

Fixes

- Fix a few glaring typing issues

Misc

- Switch to `pyproject.toml` for configuration
- Add and follow a bunch of linting rules
- Improve docstrings
- Fix a few typos

Fixes
Control server session writes only once per listen iteration

Fixes
Server response now always ends with newline

Fixes
Server's control session did not stop reading from socket after newline

Fixes
Bug in control parser due to missing docstring in `until_closed` method

Features

Add `until_closed` method to pools