Make OWM and WAPI mappings independent

[nhoening]

We actually are mapping OWMs response fields to FlexMeasures' internal names and sensor representation. A crucial part of code in this plugin.

I found out that when calling WeatherAPI, we are first translating its responses into the OWM format (in map_weather_api_to_owm()) and then let the usual mapping code run.

We should actually make them independent of each other (imagine OWM changes its format, then your WeatherAPI code breaks also). Two mappings in sensor_specs.py, and then save_forecasts_in_db() only selects the right one. Much cleaner.

(Something I should have caught in an earlier review, sorry)

[devansh287]

Totally understand your concern @nhoening. We are rolling out an internal feature right now, so just wanted to let you know that I will take a look at this 1-2 weeks from now, unless you think this is really urgent.

[nhoening]

That's fine, as this works for now - it's just not very future-proof (or easy to read). Looking forward to review!

[devansh287]

Hi @nhoening, really appreciate your patience on this matter. I have tried to address the issue via #11, please review.