Adding an example of NIM

[deep-diver]

Adding an example of NIM

[Bihan]

Hey @deep-diver,

1. I’ve created a sample README.md that follows dstack's structure. Please note that it assumes the reader is already familiar with NIM. Feel free to update it accordingly.
2. I tested the sample configuration with a 24GB GPU, and it worked. Kindly update the GPU requirement to 24GB.
3. Could you also provide the source-code for the development environment (.dstack.yml), task (task.dstack.yml), and service (service.dstack.yml)

Thanks!