Allow to set-up MapStruct for Java projects through the plug-in

まだ誰も着手していません。

When working with a Maven project for which MapStruct is enabled (e.g. through via maven-processor-plugin), upon import of the project M2E will automatically configure the Eclipse project to run the MapStruct annotation processor.

But for plain "Java Project"s it'd be nice if the plug-in could be used to set up MapStruct. It could like this:
- Under "Project Properties" have an entry "MapStruct"
- On that page have a check box "Enable MapStruct for this project"; When checked this should register the annotation processor (AFAIK there is an extension point through which APs can be registered)
- Allow to specify the processor options through check boxes as well
- Optionally, have a global preferences pane which can be used to configure default values for the processor options which would be overridden by project-scoped settings

@larswetzer WDYT, would that make sense?

まず、Eclipse の annotation processor 登録用 extension point と、通常の Java プロジェクトに対してプロジェクトプロパティおよびグローバル設定がどのように提供されるかを確認します。プラグインで MapStruct を有効化し、プロジェクトスコープでプロセッサオプションを設定でき、さらに任意でデフォルト値を提供しつつ、プロジェクト設定でそれを上書きできれば完了です。

索引モデルが issue の本文から書いたものです。