Add stuck_script_handler.sh

Devised to be run from a crontab or directly.
- Checks a given script or process name for elapsed running time
- If elapsed time is greater than the specified maximum time, kills the process
- Optionally deletes the lockfile at /var/lock/scriptname.sh  where scriptname.sh is the first argument (the script being checked). This should be an empty lockfile created to protect non-concurrency-safe scripts against simultaneous execution. If the script can't verify the file's existence, it will exit with an error state.