Provide an option to disable import ordering or customize order

I'm working on a project ([Apache Flink](https://github.com/apache/flink)) using AOSP format but with [customized import ordering](https://github.com/apache/flink/blob/e0240c782073f879a1a1e3fe22b45a38ee499c45/pom.xml#L2123-L2126). I manually set the order in `Preferences | Editor | Code Style | Java | Imports | Import Layout`, but `google-java-plugin` will override my settings when I use "Optimize Imports".

Is it possible to provide an option to disable the feature, or let users to customize the import order? Thanks!