* Reduce data sharing between ConfigFlow and DataUpdateCoordinator
Instead of fetching device information from the device once in
`ConfigFlow` and then piping it through in `ConfigEntry.data`,
only use as much as needed in `ConfigFlow.async_step_user`, then fetch
again in `AirQCoordinator._async_update_data` if a key is missing.
Additionally, factor `AirQCoordinator` out into a sumbodule.
Add a simple test for `AirQCoordinator.device_info` update.
Positive side effect: `AirQCoordinator.device_info` is
updated explicitly, instead of dumping the entire content of (a fully
compatible) `TypedDict`, retrieved from `aioairq`.
* Remove tests ill-suited to this PR
`test_config_flow.test_duplicate_error` slipped through by mistake,
while `test_coordinator.test_fetch_device_info_on_first_update` may need
a more thoroughly suite of accompanying tests
* Ignore airq/coordinator.py
...newly separated from airq/__init__.py, that's already in this list
* Reorder files alphabetically
Erik Montnemery
Renat Sibgatulin