feat: run command

[vansangpfiev]

https://github.com/janhq/cortex/issues/1076

.\cortex-cpp.exe run tinyllama:gguf
20240829 04:37:36.360000 UTC 15764 INFO  Downloading item: tinyllama-gguf - download_service.cc:35

20240829 04:38:08.108000 UTC 15764 INFO  Downloading item: cortex.llamacpp - download_service.cc:35

Inorder to exit, type `exit()`
> How are you today?
I'm fine. How about you?
> exit()

[namchuai]

looks good to me. Just some nit picking. 💯