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

CODEOWNERS

@@ -206,7 +206,7 @@ homeassistant/components/mcp23017/* @jardiamj
 homeassistant/components/mediaroom/* @dgomes
 homeassistant/components/melissa/* @kennedyshead
 homeassistant/components/met/* @danielhiversen
-homeassistant/components/meteo_france/* @victorcerutti @oncleben31
+homeassistant/components/meteo_france/* @victorcerutti @oncleben31 @Quentame
 homeassistant/components/meteoalarm/* @rolfberkenbosch
 homeassistant/components/miflora/* @danielhiversen @ChristianKuehnel
 homeassistant/components/mikrotik/* @engrbm87