Option to not use SSH

[maximelebastard]

Some SCP server images, for security reasons, allow to be used with scp only. We can't do any ssh command on it. This is done using rssh. This is the case of eeacms/scp-server for example.

It causes drone-scp to fail on the first directory creation called here

Is it something simple to create an option for drone-scp to use scp commands only ?

[appleboy]

@maximelebastard I will add the new flag to ignore create target folder.