add SSHOptions to interface, allows parsing from SSH options that are
called via ssh -o Option=Value.
follow DIRAC code conventions.
correction, ssh-options are itemwise passed, so SSHOptions works as
placeholder for any allowed arg in ssh/scp
fix
empty
Merge pull request #1928 from zimmerst/rel-v6r10-SSH_options

[v6r10] add SSHOptions to interface, allows parsing from SSH options that are
v6r10p23
v6r11-pre17
Conflicts resolved with rel-v6r10