UI unit testing without Chrome

In http://review.couchbase.org/c/cbmultimanager/+/161604/3 I added unit tests for the UI, however they run using the Karma runner - it's recommended by Angular, but it relies on running the tests in a Chrome instance. This is suitable for end-to-end tests (which we should also eventually have), but is overkill for simple unit tests.

Investigate if it's possible to run Karma tests using something like jsdom instead of Chrome. If not, investigate alternatives to Karma. (I've had decent experiences with Jest, though I don't know how well it works with Angular.)