* Android: Add local copy of native_app_glue, patched to compile as C++.
* Android: List android-x86_64 configuration in makefile
* Android: Build shared-lib and examples by default
* Docs: Update Android build prerequisites
* CI: Add Android builds
* CI: **DO NOT MERGE** pick bx/PR with android support update
Changes:
* Move the project generation command in prepare step to run in host ubuntu-22.0 os.
* Add EMSCRIPTEN explicitly in both prepare and build step.
* Run make command with respect to root bgfx workspace directory.
