[Feature] Allow cronjobs to be recreated

[sdalmeida]

OS: ethOS

I had storjdash configured and once I updated my machine, all cronjobs where cleared. I can't run sudo register_storjdash since the config file was created from before. I had to rename my config file, run the command from above and replace the newly created config with the old one.

It would be nice if there was a separate command for recreating a cronjob if one doesn't already exist.