gltfio: Move the API for recomputeBoundingBoxes.

Prior to this change, `recomputeBoundingBoxes` was an opt-in config
parameter in ResourceLoader. It is now a method on FilamentInstance.

The old API did not work for dynamically created instances. Since this
is a relatively obscure feature, we considered removing it completely,
especially since the computation requires the presence of CPU-side
vertex data combined with the transform hierarchy.

Instead of removing the feature, we decided to move it to a better
place. This paves the way for some upcoming improvements, which include
reducing the memory footprint for assets. It also improves overall code
organization and separation of concerns.

android/gltfio-android/src/main/cpp/ResourceLoader.cpp

@@ -36,11 +36,9 @@ static void destroy(void*, size_t, void *userData) {
 
 extern "C" JNIEXPORT jlong JNICALL
 Java_com_google_android_filament_gltfio_ResourceLoader_nCreateResourceLoader(JNIEnv*, jclass,
-        jlong nativeEngine, jboolean normalizeSkinningWeights, jboolean recomputeBoundingBoxes,
-        jboolean ignoreBindTransform) {
+        jlong nativeEngine, jboolean normalizeSkinningWeights) {
     Engine* engine = (Engine*) nativeEngine;
-    return (jlong) new ResourceLoader({ engine, {}, (bool) normalizeSkinningWeights,
-            (bool) recomputeBoundingBoxes, (bool) ignoreBindTransform});
+    return (jlong) new ResourceLoader({ engine, {}, (bool) normalizeSkinningWeights});
 }
 
 extern "C" JNIEXPORT void JNICALL