chore: use Policyfile dependency resolution

[damacus]

Summary

• move dependency resolution to Policyfile
• remove stale Berkshelf files/references where present
• update Copilot setup/docs to use chef install Policyfile.rb where applicable

Testing

• chef install Policyfile.rb
• cookstyle
• chef exec rspec --format documentation: 65 examples, 0 failures

[github-actions]

Slowest examples

Top 10 slowest examples (0.73 seconds, 30.26% of total time)

Example	Description	Time in seconds
spec/unit/resources/consul_service_spec.rb:39	consul_service action :start is expected to start service "consul"	0.14795
spec/unit/resources/consul_installation_spec.rb:29	consul_installation with binary install method is expected to create remote_file "/tmp/d20260630-2334-91xflm/consul_1.22.5_linux_amd64.zip"	0.11582
spec/unit/resources/consul_config_spec.rb:46	consul_config with custom config_dir is expected to create directory "/etc/consul/custom.d"	0.10265
spec/unit/resources/consul_acl_spec.rb:20	consul_acl creates an ACL is expected to create consul_acl "test-acl"	0.0729
spec/unit/resources/consul_service_spec.rb:18	consul_service action :enable is expected to enable systemd_unit "consul.service"	0.05466
spec/unit/resources/consul_installation_spec.rb:42	consul_installation with binary install method and custom checksum is expected to create remote_file "/tmp/d20260630-2334-ja80k7/consul_1.22.5_linux_amd64.zip"	0.0484
spec/unit/resources/consul_token_spec.rb:18	consul_token creates a token is expected to create consul_token "test-token"	0.04757
spec/unit/resources/consul_service_spec.rb:80	consul_service action :disable is expected to disable systemd_unit "consul.service"	0.0475
spec/unit/resources/consul_watch_spec.rb:29	consul_watch action :delete is expected to delete file "/etc/consul/conf.d/app-deploy.json"	0.04704
spec/unit/resources/consul_watch_spec.rb:17	consul_watch creates a watch is expected to create directory "/etc/consul/conf.d"	0.04697