Added initial markup, styles, and icons for displaying a menu on the top of the screen.
Has rudimentary support for responsive design, but the mobile view presently just hides the menu items.
Pivotal task: #60204486
Merge remote-tracking branch 'origin/master'

* origin/master:
  Tweaked TA policy to exclude hashCode methods Added unit tests for MongoUtils and MongoHealthCheck Moved some test classes to appropriate packages
  Address code review, round 2: replace assertTrue() with assertThat().isTrue()
Added CSS rules to collapse the menu options into a 'menu' button for mobile
Added placeholder text to test longer page lengths
Pivotal task: 934766-60204486
Moved top navigation menu into a Ember component in order to toggle the open and closed states of the mobile menu. [Finishes #60204486]