fix: migrate to Policyfile

[damacus]

Summary

• add Policyfile.rb and remove Berksfile
• update ChefSpec and Copilot dependency setup for Policyfile
• remove stale Berkshelf packaging ignores and references

Verification

• chef install Policyfile.rb
• cookstyle --no-server --cache-root /private/tmp/rubocop_cache
• /opt/homebrew/bin/markdownlint-cli2 "**/*.md"
• env GEM_HOME=/opt/chef-workstation/embedded/lib/ruby/gems/3.1.0 GEM_PATH=/opt/chef-workstation/embedded/lib/ruby/gems/3.1.0 /opt/chef-workstation/embedded/bin/rspec
• git diff --check
• kitchen list
• KITCHEN_LOCAL_YAML=kitchen.dokken.yml kitchen list

[github-actions]

Slowest examples

Top 10 slowest examples (1.3 seconds, 36.55% of total time)

Example	Description	Time in seconds
spec/unit/resources/nodejs_repository_spec.rb:15	nodejs_repository on ubuntu is expected to install package "["ca-certificates", "curl", "gnupg", "apt-transport-https"]"	0.1713
spec/unit/resources/nodejs_repository_spec.rb:18	nodejs_repository on ubuntu is expected to add apt_preference "nodesource"	0.16619
spec/unit/library/helper_spec.rb:18	helper methods npm_dist should return a url based on the version	0.16178
spec/unit/resources/nodejs_install_spec.rb:89	nodejs_install source install is expected to create link "/usr/local/bin/python"	0.15126
spec/unit/resources/nodejs_install_spec.rb:33	nodejs_install package install on rocky linux is expected to disable dnf_module "nodejs"	0.13768
spec/unit/resources/nodejs_install_spec.rb:35	nodejs_install package install on rocky linux is expected to install package "nodejs-devel"	0.12936
spec/unit/resources/nodejs_install_spec.rb:15	nodejs_install package install on ubuntu is expected to create nodejs_repository "nodesource"	0.12796
spec/unit/resources/nodejs_repository_spec.rb:17	nodejs_repository on ubuntu is expected to create remote_file "/etc/apt/keyrings/nodesource.asc"	0.09
spec/unit/resources/nodejs_install_spec.rb:90	nodejs_install source install is expected to install_with_make ark "nodejs-source"	0.08547
spec/unit/resources/nodejs_install_spec.rb:88	nodejs_install source install is expected to install package "python3"	0.08494