npm_modules: Fork bower_components into Polymer 0.4.0 and 0.5.0 versions

Newly created polymer elements are only available in Polymer 0.5.0.
This change adds a Polymer 0.5.0 version of bower.json to npm_modules for
Chrome infra apps to use.
Legacy app code will still continue to be able use Polymer 0.4.0.

Summary of change (since diff is too ugly):
 - Move existing bower.json and bower_components into polymer_0.4.0 directory.
 - Copy bower.json into polymer_0.5.0 directory.
 - Update all Polymer 0.4.0 references to 0.5.0 and remove conflict
   resolution rules in polymer_0.5.0/bower.json file.
 - Run "bower update" in polymer_0.5.0.

Review URL: