feat: split out npm versioning from semver (#3023)

lib/config/definitions.js

lib/manager/npm/extract/index.js

lib/versioning/cargo/index.js

lib/versioning/composer/index.js

lib/versioning/hashicorp/index.js

lib/versioning/node/index.js

lib/versioning/npm/index.js

lib/versioning/npm/range.js

lib/versioning/semver/index.js

test/versioning/npm.spec.js

test/versioning/semver.spec.js

test/workers/repository/process/lookup/index.spec.js

...ers/repository/updates/__snapshots__/flatten.spec.js.snap