Unified shared libraries

Shared libraries in ndk platforms dir are just for linking at compile time. They already exist on device and are never included in apk. So are the real libraries necessary in NDK? Apple has a good solution. They use text files instead of binary dylib for the linker, for example `libz.tbd`. `tbd` file contains export symbols, archs, version, min os version of some symbols etc. The advantage is obvious. The whole sysroot will be very small(<10M instead of ~800M), and it can support all os versions.

Start with the NDK platforms directory and the shared libraries used for compile-time linking; compare their current contents with the Apple .tbd approach described here. Define and validate a replacement that preserves required exports, architectures, and OS-version metadata while meeting the proposed sysroot-size and compatibility goals.

Written by the indexing model from the issue text.