Option to ask if file should be overwritten

[detzt]

I don't want to auto override every file so I leave this in the settings unchecked.
Sometimes I would like to override a file so I have to either check that temporarily or even have to delete the file and download it again if I don't want to have every file overwritten.
So here is my suggestion:

Add the option to ask for every updated file, if it sould be overwritten or not.

The selection doesn't have to be saved, just a littly message to choose.

[detzt]

I'm currently not good enough at C++, but this would only need to change the calculation of downloadFile in browser.cpp around line 183 to something like:

bool downloadFile = true;
bool modified = QFileInfo(directory, filename).lastModified().toMSecsSinceEpoch()/1000 < currentElement->data(dateRole).toDateTime().toMSecsSinceEpoch()/1000;
if(directory.exists(filename))
{
    if(modified)
    {
        downloadFile = options->isOverrideFilesCheckBoxChecked();
        if(options->isAskForOverrideFilesCheckBoxChecked()) // Entsprechende CheckBox muss dem UI hinzugefuegt werden
        {
            // downloadFile = Utils::confirmMessageBox("Soll die Datei "+info+" ueberschrieben werden?");
            // In der obigen Zeile soll nachgefragt werden, allerdings kenne ich die Befehle nicht.
        }
    }
    else
    {
        downloadFile = false; // Datei unveraendert
    }
}