[Files.app] Split navigation_list.js into the model and UI parts

This CL just splits the navigation_list.js.

BUG=none
TEST=none
TBR=hirono@chromium.org

Review URL: https://codereview.chromium.org/48193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231300 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 231300