Remove Stove from Gemfile & Rakefile

Works best if its just installed on its own
Update to RuboCop 0.23.0
Use Berkshelf ~> 3.1.0
Use our internal Berkshelf API Server
Remove ChefSpec Chef Zero usage, add command stubbing to fix tests
Update to ChefSpec ~> 4.0
Convert Serverspecs to RSpec 3.0.1 syntax with Transpec

This conversion is done by Transpec 2.2.4 with the following command:
    transpec -f test/integration/default/serverspec/

* 23 conversions
    from: it { should ... }
      to: it { is_expected.to ... }

* 4 conversions
    from: its(:attr) { }
      to: describe '#attr' do subject { super().attr }; it { } end

For more details: https://github.com/yujinakayama/transpec#supported-conversions