iOS ti.ffmpeg v1.0.0

The iOS version of the ti.ffmpeg module implements the same interface as the Android module (so they are compatible), and adds two new features: the log event to stream logs back to the caller and multiple inputs (options.inputs). Multiple inputs allows defining multiple input files and options for each. The iOS version uses the ffmpeg-kit-min-6.0-ios-xcframework libraries (min to reduce file size). There is a test harness application in example/app.js