_sandboxremote.py: Add sigterm handler that sends CancelOperation
Description
Set up handler to make a CancelOperation when jobs are terminated.
Only _sandboxremote.py
needs to be changed with a signal handler around the operation stream, and a new cancel_operation
method.
Ideally with #629 (closed) closed an integration test could make sure this works.
Closes #725 (closed)
Edited by Raoul Hidalgo Charman