Do not vendor cookbooks using Berkshelf anymore

Instead, use the Berkshelf support in knife-solo and the
vagrant-berkshelf plugin on Vagrant

cookbooks/hostname/.rubocop.yml

@@ -1,23 +0,0 @@
-AllCops:
-  DisplayCopNames: true
-  Exclude:
-    - tmp/**
-
-Lint/AmbiguousBlockAssociation:
-  Enabled: false
-
-Metrics/BlockLength:
-  Enabled: false
-
-Metrics/LineLength:
-  Enabled: false
-
-Style/Documentation:
-  Exclude:
-    - Thorfile
-
-Style/PercentLiteralDelimiters:
-  Enabled: false
-
-Style/SingleSpaceBeforeFirstArg:
-  Enabled: false