Test kitchen, plugin updates, admin password, packer enhancements

[vrivellino]

Hey guys, I've been working on our Jenkins setup as as our AMI building at my new gig and wanted to share some enhancements for tophat.

This pull request ...

• Updates to the latest Amazon AMI
• Adds test kitchen, as well as serverspec tests, to the project
• Adds a bash script resource to the jenkin-config:jenkins-plugins recipe that ensures all plugins are up-to-date. I'm not sure it's the cleanest way to accomplish this (Jenkins is restarted a few times, and that resource must run before auth is setup).
• Adds the jenkins-auth recipe which sets a default admin password, sets matrix authorization strategy, and give anonymous read-only.
• Enhances the packer config with a helper script and running infrastructure tests after chef runs. This ensures that an AMI won't get created unless tests pass.

NOTE: In this PR, I'm just doing gem install serverspec in the inline script in jenkins.json as a quick and dirty way to get serverspec installed. At Demyst, we're using rbenv everywhere, and we're installing the gem via a LWRP via the ruby_rbenv cookbook.

[BrianJakovich]

Hey Vince, thanks for submitting this! I'll merge it in once I get a chance to look through it.