candolint: add configuration file

viewer: show "unknown" in status badge when no checks have been done yet

queue: if there's no event header, set event to 'nonexistent'

tests: don't ignore exit code from pytest.main()

tests: test hook handlers in hooks-queue.py

queue: let's just call it event

queue: move option creation to main() to help with tests

viewer: move option creation to main() to help with tests

queue: turn HTTPErrors into JSON responses via BaseHookHandler.write_error()

queue: log event type that hook handlers receive