Separate configuration section for jump server (front-end-to-jumpbox) connection parameters

NetBrain currently provides only a single configuration field, the CLI Command to Connect, for jump server (jumpbox) setups. This field is used to define the command for connecting from the jumpbox to target devices, but there is no separate mechanism to configure or optimize the connection between the NetBrain Front Server and the jumpbox itself, such as enabling SSH tunnel multiplexing to avoid establishing a new tunnel for every backend connection. This enhancement would introduce a distinct configuration section, for example within the Advanced tab of jumpbox definitions, dedicated to Front Server-to-jumpbox connection parameters. This section would support SSH multiplexing options such as control master and control path settings, allowing a single tunnel to be reused across multiple backend sessions. Customers using jump servers at scale would benefit from reduced resource consumption on both the Front Server and the jumpbox, since a persistent multiplexed tunnel avoids the overhead of establishing a full SSH tunnel for every device connection.