add verifySignature method in wyUtils
(cherry picked from commit f66ba74f480cc652cc53264eec873acf79f47ccc)

Conflicts:
	jni/WiEngine/include/utils/wyUtils.h
(cherry picked from commit db123176d26b8a8ef0859461b52d69fdd932ca25)

Conflicts:
	jni/WiEngine/impl/platform/android/wyUtils_android.cpp
	jni/WiEngine/impl/platform/ios/wyUtils_ios.cpp
	jni/WiEngine/impl/platform/macosx/wyUtils_macosx.cpp