Instead of auto-detecting which transport class to use, the instances configuration
now supports a new setting named `transport' with the possible values 'local' and 'remote'.
refs #6593
`RemoteCommandFile' is configured via property setters instead of the too general `setEndpoint' function.
The ssh command to be executed only has the option 'BatchMode' set to 'yes' as this is enough to disable
interactive authentication methods. Further, all arguments become espaced.
refs #6593
