refactor: move ExternalHostError

lib/config/presets/github/index.ts

lib/config/presets/gitlab/index.ts

lib/config/presets/index.ts

lib/constants/error-messages.ts

lib/datasource/cdnjs/index.ts

lib/datasource/crate/index.ts

lib/datasource/dart/index.ts

lib/datasource/docker/index.ts

lib/datasource/galaxy/index.ts

lib/datasource/gradle-version/index.ts

lib/datasource/helm/index.ts

lib/datasource/hex/index.ts

lib/datasource/index.spec.ts

lib/datasource/index.ts

lib/datasource/maven/util.ts

lib/datasource/npm/get.spec.ts

lib/datasource/npm/get.ts

lib/datasource/packagist/index.ts

lib/datasource/pod/index.ts

lib/datasource/repology/index.ts