Nordpool day-ahead spot price API

[Millox]

This PR adds support for using the Nordpool api which provides price data for 14 countries, and 22 areas with local currencies and EUR.

Would fix
#17464
#17479
#17580

May replace or supersede tariffs from
energinet
elering

Related to:
#17582
#17493

[andig]

Nice and complete PR! But do we really need a Go module? Isn‘t JQ sufficient here? #17582 showcases how.

[Millox]

Most likely jq would be sufficient but that would have been more work since I already had the structs for json unmarshalling ready and just basically reused the code from elering/energinet that already existed. Making it for jq would have been more work.

[andig]

We can‘t merge this. Adding code that needs be maintained without need is not a good idea, sorry.

[andig]

It doesn't quite seem to work either:

https://dataportal-api.nordpoolgroup.com/api/DayAheadPrices?currency=SEK&date=2024-12-08&deliveryArea=SE4&market=DayAhead

yields

HTTP/2 204 

[Millox]

The 204 return code is due to there not being any data available for that day yet.

So, would it be possible if implemented in another way? Using Nordpool data is the only way to get correct prices for SE, NO and DK (however DK have proxied data from energinet, which is not available for NO/SE). Is the correct way forward to implement it using jq?

I ask because there is no other way to get pricing accurately for us living in NO/SE and this api also provide the same data as Energinet and Elering, which if those are removed/deprecated then the codebase actually decrease in size.