Add .travis.yml configured to run eslint, and fix existing lint errors

[mturley]

This PR adds a basic Travis CI configuration file which will run yarn test, and a test script in package.json which for now simply runs the lint package script (which runs eslint). In the future we can add Jest tests to the test package script, and we can add things like CodeClimate to the Travis configuration.

[mturley]

Not sure what exactly to do here to fix the Ruby check failures, looks like rake app:test:vmdb:setup is failing. It's probably related to the rspec stuff I ripped out temporarily.. @Fryguy do you think it's ok if I remove the Ruby checks from Travis for now and we revisit that when we're ready to look at Ruby tests here? Or would you rather I set up those tests in this PR?

[mturley]

For now, I removed the Ruby checks so I can unblock this PR (since it contains JS changes that will conflict with my next PR). Opened this issue to revisit it in another PR: #2