Bundle: Nit API wrapping Bundle class

The Bundle class is an Android API custom mapping class. It maps `String` to various value types. This class is used by a lot of android callbacks and classes in general. It is mainly used to communicate data between application entities. 

Required by the `Intent` API

Signed-off-by: Frédéric Vachon <fredvac@gmail.com>
Je me serais plus attendu à la signature `fun [](key: String): nullable Serializable`