PoC for using JSI instead of platform binary

[BitcoinZavior]

Current implementation uses Android and iOA binaries as core modules for providing bdk functionality.

Do a Proof of concept to explore use of JSI interface to C++ as a alternate mechanism instead of using platform binaries.

This has a number of advantages:

• Eliminates constraints of RN bridge
• Will allow reuse of bdk ffi rust code directly thus providing more api
• Will reduce effort and maintenance in using native wrapper code in Android and iOS
• Performance improvements
• Eliminate cold start time