Provide a hook that runs after Workbench has complete executing

[mjordan]

https://mjordan.github.io/islandora_workbench_docs/hooks/ documents the hooks Workbench provides. There is no "shutdown" hook, which would be useful, for example, in cases where the use of Workbench is automated. For example, a shutdown script could scan the log to see if some nodes/media failed to be created, and if any are found, email the log to someone.

[mjordan]

Adding this to a config file will execture the named script: shutdown: ['scripts/shutdown_example.py'] .