Add support for csv separator selection on grid loading

[johanneshiry]

Currently, there is only support of loading csv files with semicolon as separator. However, this is not a limitation of the actual csv reading and parsing mechanism (because the used PSDM reader supports file separator selection) but a missing configuration dialog on loading the grid.

Should be easy to implement to show a dialog before calling the corresponding sources.

[ckittl]

Where are you missing this feature? There is a drop down menu available when loading the grid and to me, it actually works... 🤔