API forecast/all forecast_horizon

[peterdudfield]

Allow forecast/all route to get 4 hour view.

Add two new variables to v0/solar/GB/gsp/forecast/all/

• forecast_horizon_minutes
• only_forecast_values

/forecast/all uses /src/database.py - get_forecasts_from_database function

if only_forecast_values then we can uses

    forecast_values = get_forecast_values(
        session=session,
        gsp_id=range(0,N_GSPS),
        start_datetime=start_datetime,
        only_return_latest=True,
        forecast_horizon_minutes=forecast_horizon_minutes,
        model=ForecastValueSevenDaysSQL,
    )

This should be in historic==False section.

TODO

Need to think how this object should be returned. It cant just be a list of ForecastValues as that doesnt include the location (gsp_id).

openclimatefix/nowcasting_datamodel#144

It could be made into a list of Forecasts but this might require a bit of manipulating, so there is only one Forecast for each gsp_id. We could do this in the datamodel, so that the api deosnt need to worry about it

Data model:

datamodel has been adapted here - openclimatefix/nowcasting_datamodel#143