Using prebuilt binaries

[Vali-98]

For better developer experience, llama.rn should prepackage the rn-llama.cpp binary. Currently, it takes about 10-15 minutes to build, which massively slows down CD flows for no real reason. Though I personally run a ccache service to cache redundant builds, it would be ideal if the package simply had the binaries ready-made.

An example of this is how expo-sqlite packages the crsqlite extension:

https://github.com/expo/expo/tree/sdk-51/packages/expo-sqlite/android/src/main/jniLibs/arm64-v8a
https://github.com/expo/expo/tree/sdk-51/packages/expo-sqlite/ios/crsqlite.xcframework/ios-arm64/crsqlite.framework