Add type and direction infos in Annotation class

background issue https://github.com/Microsoft/azure-maven-plugins/issues/456

There used to be strong dependency between function maven plugin and function java library, and now we change to use java reflect to get attributes from annotation to reduce the dependency (PR https://github.com/Microsoft/azure-maven-plugins/pull/508).
However, we still need to store annotation type and direction infos in our enum class for we can't get them from annotations. So could you please add the infos in annotations of java library, like add an annotation? If so, all needed informations could comming from java library directly.
Besides, could you please update the [function.json scheme](http://json.schemastore.org/function)? Schema could be much helpful in local validation and users could verify and update their code according to schema as well

まず Annotation クラスと既存のアノテーション enum から始め、コンテキストを把握するために、リンクされている背景 issue と reflection 関連の pull request を確認します。必要な型情報と方向情報を公開するように Java アノテーションを更新し、それらの値を検証できるように、参照されている function.json スキーマを更新します。

索引モデルが issue の本文から書いたものです。