Add form input for charging station output

[tykayn]

The osmose analysis for charging station has been updated to handle power output in kilowatts, we should add a field in the form for the charging station theme. The wiki says the default unit is in kW, and marking the unit is not mandatory.

How do we manage that in the config ?
Knowing that the Osmose Analysis returns the value like "250 kW" for the key charging_station:output key, and that we also have this kind of data for each socket.

[PanierAvide]

I guess the issue could be break down into multiple things :

• Not setting the kW unit if that's the default : to report on Osmose side
• Adding an input for showing/changing the value, here in fields list (either hidden or text depending on how we are confident about this) https://github.com/osm-fr/podoma/blob/master/projects/2020-03_evcharging/info.json
• Station vs socket : 🤷‍♂️ I haven't followed recent changes, I think we still manage station-level in pdm.fr, not single sockets