add nn-cli example (#4373)

an example application with flexible cli options which
aims to allow us to perform any wasi-nn operations.

eg.
```
--load-graph=file=fixture/model.xml,file=fixture/model.bin,id=graph
--init-execution-context=graph-id=graph,id=ctx
--set-input=file=fixture/tensor.bgr,context-id=ctx,dim=1,dim=3,dim=224,dim=224
--compute=context-id=ctx
--get-output=context-id=ctx,file=output.bin
```

wamr-wasi-extensions/test.sh

@@ -20,6 +20,12 @@ cmake -B build-app-nn \
 samples/nn
 cmake --build build-app-nn
 
+cmake -B build-app-nn-cli \
+-DCMAKE_TOOLCHAIN_FILE=${WASI_SDK}/share/cmake/wasi-sdk.cmake \
+-DCMAKE_PREFIX_PATH=${PREFIX} \
+samples/nn-cli
+cmake --build build-app-nn-cli
+
 cmake -B build-app-socket-nslookup \
 -DCMAKE_TOOLCHAIN_FILE=${WASI_SDK}/share/cmake/wasi-sdk-pthread.cmake \
 -DCMAKE_PREFIX_PATH=${PREFIX} \