Removed `Android.mk` and `Application.mk`, allowing `CMake` to run directly from the `build.gradle` file. Users no longer need to check out `NDK` or depend on it, simplifying the usage of the IAMF extension.
PiperOrigin-RevId: 684471874
In order to support building with `gradle` a new `build.gradle` file was added together with `Android.mk`, `Application.mk`, and `libiamf.mk` necessary for local builds with NDK.
After this change, IAMF files may also be played in the ExoPlayer demo built locally (without blaze).
PiperOrigin-RevId: 664841684
