Dependency Proxy uses workhorse for manifest pulls

...lers/groups/dependency_proxy_for_containers_controller.rb

app/helpers/workhorse_helper.rb

app/models/dependency_proxy/blob.rb

app/models/dependency_proxy/manifest.rb

...vices/dependency_proxy/find_or_create_manifest_service.rb

...flags/development/dependency_proxy_manifest_workhorse.yml

config/routes/group.rb

doc/administration/instance_limits.md

...groups/dependency_proxy_for_containers_controller_spec.rb

lib/gitlab/workhorse.rb

...groups/dependency_proxy_for_containers_controller_spec.rb

spec/lib/gitlab/workhorse_spec.rb

spec/models/dependency_proxy/manifest_spec.rb

spec/requests/rack_attack_global_spec.rb

spec/routing/group_routing_spec.rb

.../dependency_proxy/find_or_create_manifest_service_spec.rb

workhorse/internal/dependencyproxy/dependencyproxy.go

workhorse/internal/dependencyproxy/dependencyproxy_test.go