Make mobile-install work with rules_jvm_external

[fhilgers]

Possibly fixes #232

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[fhilgers]

The easier solution would probably be to set the package field of aar_import in rules_jvm_external. Should there maybe be a warning if that field is unset or if the package name inferred from field and label is empty?

[ted-xie]

This should be resolved by https://github.com/bazelbuild/rules_android/commit/9e40a7875043d018f8a2e60ed0b5628f694d7b09.