Add config flow to Meteo-France (#29927)

* Add config flow to Meteo-France

* Review 1

* Use config_entry.unique_id

* Fix config_flow _show_setup_form + init

* Remove empty *_setup_platform()

* Avoid HomeAssistantError: Entity id already exists: sensor.[city_name]_[sensor_type]. Platform meteo_france does not generate unique IDs

- when multiple district in one city

* Review + abort when API error

* Fix I/O

* Remove monitored_conditions

* Add async_unload_entry

* Review 3

* Fix pipe

* alert_watcher is already None

* Review 4

* Better fix for "Entity id already exists"

* Whoops, fix tests

* Fix string

homeassistant/generated/config_flows.py

@@ -54,6 +54,7 @@ FLOWS = [
     "luftdaten",
     "mailgun",
     "met",
+    "meteo_france",
     "mikrotik",
     "mobile_app",
     "mqtt",