SSH Public Key Authentication Support for Device Discovery

NetBrain discovery currently does not support authenticating to devices using SSH public key credentials; only standard username and password based authentication is supported for establishing device sessions during discovery. This enhancement would allow administrators to configure and apply SSH key-based authentication (including specifying a private key file) as a valid credential method for device discovery. Customers whose network devices are configured to require or prefer public key authentication would be able to complete discovery successfully without falling back to less secure or unsupported authentication methods.