This patch adds the ability to build custom chromium-as-release (CaR) for the android platform (arm64).
A linux host is used for the android builds so a new dockerfile is added to maintain as either platform (e.g. Linux and Android) may
have differing dependencies and potentially diverge further in the future.
We can look into consolidating them into one dockerfile later if needed.
Differential Revision: https://phabricator.services.mozilla.com/D189604
