Add support for ssh/sftp storage

[Pinetrax]

Add support for ssh/sftp storage. Just like with webdav, it is an excellent way to cover many storage solutions (like your own server or local pc, raspberry pi, ...) additional to the cloud storage providers supported right now and most of the time does not require any additional setup. You could even bridge a service with your own server when it is mounted there, although I would not recommend chaining services like that. With encryption, even ftp wound be viable.

[microcreators]

... and if that could come with rclone config support that has sftp mountpoint defined (with key auth in it), I'd be happy to donate ;)