Build sherpa-onnx as a single shared library (#1078)

When `-D BUILD_SHARED_LIBS=ON` is passed to `cmake`, it builds a single shared library.

Specifically, 

- For C APIs, it builds `libsherpa-onnx-c-api.so`
- For Python APIs, it builds `_sherpa_onnx.cpython-xx-xx.so`
- For Kotlin and Java APIs, it builds `libsherpa-onnx-jni.so`

There is no `libsherpa-onnx-core.so` any longer.

Note it affects only shared libraries.

kotlin-api-examples/run.sh

@@ -14,6 +14,7 @@ if [[ ! -f ../build/lib/libsherpa-onnx-jni.dylib  && ! -f ../build/lib/libsherpa
     -DSHERPA_ONNX_ENABLE_TESTS=OFF \
     -DSHERPA_ONNX_ENABLE_CHECK=OFF \
     -DBUILD_SHARED_LIBS=ON \
+    -DBUILD_SHARED_LIBS=ON \
     -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
     -DSHERPA_ONNX_ENABLE_JNI=ON \
     ..