Large rewrite of elasticluster and clusterjob tutorial

[motiwari]

This is a large rewrite of the elasticluster and clusterjob tutorial for Stats 285 which is significantly easier to follow and updated.

Test Plan: I couldn't test the webpage generation with bundle/jekyll since the Gemfile appears to be missing for the Repo. However, I walked through the tutorial from scratch and was able to verify it correctly set up elasticluster and clusterjob.

List of features upgraded and/or fixed:

• A large part of the setup is now automated in elasticluster_tutorial/setup.sh; it is now significantly easier for users (who don't have to manually modify any configs)
• There are more details about how to set up VirtualBox and the Ubuntu VM correctly
• More details about Google Cloud setup are included, including the OAuth consent form and the (required) "Cloud Storage for Firebase API" enabling
• Detailed bugfixes for super-fast key repetition or failed DNS servers in Ubuntu (some ISP's forwarding rules don't support DNS on your VM)
• Detailed discussion of how to set up SSH into the VM, especially as a work-around for copy-pasting from host to guest (there are known issues for clipboard sharing from VMs to host machine)
• Automated installation of all dependencies, elasticluster, and clusterjob, once environment variables are properly set
• Additional dependencies added which are required for the cpan commands
• Automatic creation of config files from templates
• Some other nits

My goal in performing this rewrite was to make it easier for other students and future iterations of the class. I believe the tutorial is significantly more up-to-date and easier to follow now.

Note: The new tutorial is currently stored in elasticluster_tutorial/elasticlusterjob-tutorial.md and has not currently replaced the elasticlusterjob-tutorial.md since I could not get jekyll to turn it into a .html file without the Gemfile.