Nexus writer change RUNNING state meaning
Related to #2630 (closed) but now about the session state, not the scan state.
A RUNNING session state currently means we are listening to Redis events for at least one scan (scan is active).
Change the meaning to: at least one scan is not completely finalized (scan is alive). An active scan is always alive but not vice versa. The difference is resource cleanup (like closing the HDF5 file).
Edited by Wout De Nolf