Default for `android.debug_artifact` should be dependent on `p4a.bootstrap` value.

[Julian-O]

Description

• The default value for android.debug_artifact is (always) apk. However, when p4a.bootstrap is service_library, you aren't building an apk, you are building an aar, and the default should change with it. (Failing to override leads to a build failure, as the binary isn't found.

• I think android.release_artifact should change from aab to aar as well, but I am out of my depth here, and would appreciate a second opinion to confirm.

What makes this messy is the default is set in target.py when it logically should be set in android.py, so the first step is to properly separate the concerns of Android builds from the generic target.

[misl6]

Hi @Julian-O,

I agree on both. When p4a.bootstrap is service_library, we should default to aar for both debug and release artifacts.