[wasi-nn]Add a new target for llama.cpp as a wasi-nn backend

[lum1n0us]

Minimum support:

• accept (WasmEdge) customized model parameters. metadata.
• Target wasmedge-ggml examples
  • basic
  • chatml
  • gemma
  • llama
  • qwen

---

In future. To support if required.

• Target wasmedge-ggml examples
  • command-r. (>70G memory requirement)
  • embedding. (embedding mode)
  • grammar. (use the grammar option to constrain the model to generate the JSON output)
  • llama-stream. (new APIS compute_single, get_output_single, fini_single)
  • llava. (image representation)
  • llava-base64-stream. (image representation)
  • multimodel. (image representation)
• Target llamaedge

[lum1n0us]

core/iwasm/libraries/wasi-nn/test/Dockerfile.wasi-nn-smoke needs more work. Will update it in another PR.