Optimize FMI data querying

[spaasis]

We're currently fetching data with the highest available resolution. We should allow the user to choose the time resolution so they can get e.g. daily averages for the past year, instead of hourly data.

There are "daily statistics" endpoints, e.g. https://opendata.fmi.fi/wfs?service=WFS&version=2.0.0&request=describeStoredQueries&StoredQuery_Id=fmi::observations::mareograph::daily::simple but that does seem to return data for every minute? https://opendata.fmi.fi/wfs?service=WFS&version=2.0.0&request=getFeature&storedquery_id=fmi::observations::mareograph::daily::simple&parameters=WATLEV&starttime=2024-06-18&endtime=2024-06-19&fmisid=100540

The easiest way to control the queries would be the timeStep parameters e.g. https://opendata.fmi.fi/wfs?service=WFS&version=2.0.0&request=getFeature&storedquery_id=fmi::observations::mareograph::simple&parameters=WATLEV&starttime=2024-06-18&endtime=2024-06-19&fmisid=100540&timestep=1440 BUT we should figure out what the actual result here is - is it the daily average or just a single result per day?

Resources:

• https://en.ilmatieteenlaitos.fi/open-data-manual
• https://en.ilmatieteenlaitos.fi/open-data-manual-fmi-wfs-services

The relevant queries are formed in /apis/fmi, but changing the query logic might affect /apis/fmiApi.ts as well