Format runserver access logs before logging

[lin-hongkuan]

Summary

• format runserver access-log messages with their details before passing them to the logger
• apply the same pattern to HTTP and WebSocket runserver log messages
• add a regression test that verifies the logger receives a single formatted message instead of a message plus details as a second positional argument

Fixes #576

Tests

• python -m pytest tests\test_runserver.py tests\test_cli.py -q
• python -m pytest -q tests --ignore=tests/test_packaging.py
• python -m black --check daphne\management\commands\runserver.py tests\test_runserver.py
• python -m flake8 daphne\management\commands\runserver.py tests\test_runserver.py
• git diff --check

Note: as in #583, python -m pytest -q fails in my local editable-install environment only at tests/test_packaging.py::test_fd_endpoint_plugin_installed, because the Twisted plugin file is not present under the selected site-packages path. The runtime tests pass with that packaging-only test excluded.