YADE should support send of keep-alive messages for SFTP

Desired Behavior
Introducing of the new configuration items on a SFTPFragment:

• ServerAliveInterval
  • Sets the interval in milliseconds to send a keep-alive message.
• ServerAliveCountMax
  • Sets the number of keep-alive messages which may be sent without receiving any messages back from the server.

ServerAliveInterval, ServerAliveCountMax should be supported when using a jump host.

Test Instructions

• Test Configuration
  • Use the XML Editor to setup a profile and an SFTP Fragement. Make use of the above mentioned new elements/attributes.
  • On SFTP server configure max upload speed for test user.
  • Setup a job chain with the YADE job
• Test Data
  • Create a big file (2GB)
• Test Execution
  • Run YADE job chain
• Test Results
  • Negative Results
    • None of the above settings for ServerAliveInterval and ServerAliveCountMax is used.
    • The transfer will break after some time.
  • Positive Results
    • The above settings for ServerAliveInterval and ServerAliveCountMax is used.
    • The transfer will work even if it takes a long time.