Document TypeScript migrations with the Nub loader

TypeORM documents the ts-node CLI wrappers for TypeScript migrations. The ordinary CLI also runs a verified ESM TypeScript data source and migration through a Node preload.

node --import @nubjs/loader ./node_modules/typeorm/cli.js migration:run -d src/data-source.ts

The documentation should preserve type checking and describe the decorator metadata requirement for inferred column types.