Update some Android tools versions

- Update Android build tools and Gradle plugin versions
- Raise target and compile Android SDK version to 29
- Remove a patch to compile Google Test on Emscripten for Azure Pipelines
- Update NDK version in the Azure Pipelines configuration

Set nCine major, minor and patch versions for tags

- Use timestamp based nCine version if any of the Git commands fails
- Rename version variables to resemble CMake ones

Add Azure Pipelines configuration file