safe split mode settings including size in preferences

Hi,

The problem is:
I would like to create an archive with splitted archive files by simply clicking right on a directory or file and select send to Keka..
This is already implemented but I have to set every time the split size to enable this option and it cannot be saved in the preferences.

What I would like is:
The option to set the split option including split size to be on by default so that selecting a file or directory and clicking right > context menu>services>send to Keka will create the archive in splitted files defined in the settings

### Describe alternatives you've considered
an option to do this with a command line (but without the --cli option) so that I get the gui running.

This would be very much appreciated and make automatizing possible.

Regards,

Ronaldus