Changed `SubgridContainer` to represent galvanically seperated grids#1366

danielfeismann merged 6 commits intodevie3-institute/PowerSystemDataModel:devfrom

ms/#1226-change-SubgridContainer-to-be-in-line-with-the-galvanical-seperationie3-institute/PowerSystemDataModel:ms/#1226-change-SubgridContainer-to-be-in-line-with-the-galvanical-seperationCopy head branch name to clipboard