I recently made simple application that allows to install additional data for STK on Android. It detects a path to STK data directory and extracts included content. It can be used to install full data / high quality data / additional tracks / hotfix for buggy drivers / mods / etc...
Sources are available on github:
https://github.com/deveee/stk-addons-pack
Example with Candela City can be downloaded here:
https://www.dropbox.com/s/pymo47bqvr9q1 ... g.apk?dl=0
And here is the screenshot to show how it looks: