Build android library with Buck bot

[tobrun]

In #13584 we are adding a Buck CI bot that builds the core c++ code. Would be great if we could build the java code and produce a binary (.aar) that we can use for manual testing. This integration will enables us to test the modularisation work and detect issues specific to building android code with Buck (eg. not matches resource ids).

[stale]

This issue has been automatically detected as stale because it has not had recent activity and will be archived. Thank you for your contributions.