This performs an active check of an SFTP server by testing if a connection
is successful. Optionally it is possible to put a file to the server. It is
not neccessary to create a file as the check will do that if the given file
does not exist. Also same or another file or the timestamp of a file of the
server can be fetched. The Service will go CRIT if one of the tests fails.
The name of the host
No discovery supported.