Refactor the JNI interface to make it more modular and maintainable (#802)

sherpa-onnx/kotlin-api/FeatureConfig.kt

@@ -0,0 +1,10 @@
+package com.k2fsa.sherpa.onnx
+
+data class FeatureConfig(
+    var sampleRate: Int = 16000,
+    var featureDim: Int = 80,
+)
+
+fun getFeatureConfig(sampleRate: Int, featureDim: Int): FeatureConfig {
+    return FeatureConfig(sampleRate = sampleRate, featureDim = featureDim)
+}