[FR] Provide static libraries as well

**Is your feature request related to a problem? Please describe.**
While linking an Android app's native code to .so files works reasonably well, there are a lot of unused symbols shipped in the resulting .apk, contained in the .so files.

**Describe the solution you'd like**
The AAR packages provide .a files as well, allowing linking to those and, as a result, allowing the compiling/linking machinery to strip symbols that aren't actually used by the program code, resulting in smaller .apk's.

Thus, an AAR would contain headers, static and dynamic libs, very much like [Linux distros do it](https://packages.debian.org/buster/amd64/libjpeg62-turbo-dev/filelist),

**Describe alternatives you've considered**
Right now we're building all dependencies as static libs from source.

**Additional context**
https://github.com/bk138/multivnc/blob/master/android/app/src/main/cpp/CMakeLists.txt is the project in question - would be nice to use static prefabs there :-).