Summary of sticking arbitrary Android apps on cars:
* you really need source code, and a Google Play developer account (which requires an Android phone)
* you can build anything against the correct SDK, and publish it to Google Play as an “internal test”
* apps are blocked from use when not in Park, unless you declare a permission in manifest.xml - if you declare that, the onus is on you the app publisher to implement safe lockouts (eg a map app which navigates when in drive but doesn’t permit typing an address)