make an exception to the forced 60 min mtu for EXAA prices

force sdac prices to be in sdac resolution

upgraded github action stuff

added query_unavailability_of_offshore_grid for offshore grid outages…

…. not very flexible at the moment but its a start. closes #344

make sure to sort index from splitted blocks of day ahead prices befo…

…re truncating

restores timezone conversion for day ahead prices, fixes #356

day ahead prices is now more restricted. enable document_limited and …

…make sure the fix by extending days does not interfer. fixes #350

fixed a bug when there is no data for netpositions

fix bug when requesting netpositions at a resolution which has no data

fixes generic parser to correctly handle various scenarios that can h…

…appen

discussion and inspiration for fixes from #347 and #346