Feedback: Always return `gsp_ID` and `forecastCreationTime` in responses

[JamieTaylor-TUOS]

For consistency, all calls to forecast endpoints should ideally return the forecastCreationTime and also gspID for each targetTime. This will help with interpreting the data and also with parsing API responses in a uniform/standardised manner.

Context

Difficult to work with overlapping forecasts unless the forecastCreationTime is included in the response. For some endpoints atm it is impossible to determine the forecastCreationTime e.g.

https://api.nowcasting.io/v0/solar/GB/gsp/0/forecast?start_datetime_utc=2023-09-21T00:30:00&end_datetime_utc=2023-09-22T00:00:00&creation_limit_utc=2023-09-21T00:00:00

Leaving users to assume in the above example that forecastCreationTime == creation_limit_utc may penalise OCF in validation tasks.

Possible Implementation

All forecast endpoints should always return at least the following for each targetTime:

• gsp_id
• forecastCreationTime
• targetTime
• expectedPowerGenerationMegawatts
• expectedPowerGenerationNormalized

[peterdudfield]

in the forecast/all end point you can get these things. @JamieTaylor-TUOS let me know if that works for you