Incorporate sparkmonitor with BeakerX

[LeeTZ]

https://github.com/krishnan-r/sparkmonitor is a great extension for monitoring spark jobs. We could try to make it work with current notebook and lab, and integrate it into BeakerX installation

[Ben-Epstein]

I've got this running with BeakerX with a custom build of SparkMonitor https://pypi.org/manage/project/sparkmonitor-s/releases/

But it only works after restarting the kernel once. @LeeTZ I'd be happy to work with you to get it working in a more stable way!