refactor: remove config.api and use platform dispatcher (#1114)

lib/config/index.js

lib/config/presets.js

lib/config/validation.js

lib/logger/config-serializer.js

lib/manager/docker/detect.js

lib/manager/docker/resolve.js

lib/manager/index.js

lib/manager/meteor/detect.js

lib/manager/npm/monorepos.js

lib/manager/resolve.js

lib/platform/index.js

lib/workers/branch/automerge.js

lib/workers/branch/check-existing.js

lib/workers/branch/commit.js

lib/workers/branch/index.js

lib/workers/branch/lock-files.js

lib/workers/branch/parent.js

lib/workers/branch/status-checks.js

lib/workers/package-file/index.js

lib/workers/pr/index.js