feat: add streaming express example and align with non-streaming one

templates/index.ts

templates/simple/express/README-template.md

templates/simple/express/index.ts

templates/simple/express/package.json

templates/simple/express/src/controllers/chat.controller.ts

templates/simple/express/src/routes/chat.route.ts

templates/simple/express/tsconfig.json

templates/streaming/express/README-template.md

templates/streaming/express/eslintrc.json

templates/streaming/express/index.ts

templates/streaming/express/package.json

...ates/streaming/express/src/controllers/chat.controller.ts

...es/streaming/express/src/controllers/llamaindex-stream.ts

templates/streaming/express/src/routes/chat.route.ts

templates/streaming/express/tsconfig.json