refactor(datasource/docker): Convert to class (#14194)

lib/datasource/api.ts

lib/datasource/docker/index.spec.ts

lib/datasource/docker/index.ts

lib/manager/ansible/index.ts

lib/manager/bazel/extract.ts

lib/manager/bazel/index.ts

lib/manager/bitbucket-pipelines/index.ts

lib/manager/circleci/index.ts

lib/manager/cloudbuild/index.ts

lib/manager/docker-compose/index.ts

lib/manager/dockerfile/extract.ts

lib/manager/dockerfile/index.ts

lib/manager/droneci/index.ts

lib/manager/gitlabci/index.ts

lib/manager/helm-values/index.ts

lib/manager/helmv3/artifacts.ts

lib/manager/helmv3/extract.spec.ts

lib/manager/helmv3/index.ts

lib/manager/helmv3/utils.ts

lib/manager/kubernetes/index.ts