Feature/overwrite existing (downscaled) files

[paswyss]

With this implementation, all downscaled files with the given filepattern (of the config file) get deleted prior to concatenating the downscaled products. So the parameter 'clean_outputs' can be set to false, but the files with the filepattern get overwritten. -> this has the advantage when e.g. once downscale spatial and once the points.

If wanted, an additional boolean config parameterr 'overwrite_output' could make sure, this is wanted.

The relevant changes are all between the lines 424 and 477. The res is just auto formation.

[ArcticSnow]

@paswyss , I took away all open_mfdataset() and to_mfdataset() and replace them with a concat. It seems this is where we have the conflict happening.

[paswyss]

@ArcticSnow Ah I see now, that you merged another branch. But the issue is still existing? So I will have a look and try to implement it there

[paswyss]

Should be good now. Please check again :) @ArcticSnow