[Infer] Colossal-Inference serving example w/ TorchServe (single GPU case) (#4771)

* add Colossal-Inference serving example w/ TorchServe

* add dockerfile

* fix dockerfile

* fix dockerfile: fix commit hash, install curl

* refactor file structure

* revise readme

* trivial

* trivial: dockerfile format

* clean dir; revise readme

* fix comments: fix imports and configs

* fix formats

* remove unused requirements