GenericCompositeFuture

Coordinate a List<Future<T extends Future <?>>>, provides
all(List<T>), any(List<T>) and join(List<T>) that work like
CompositeFuture#all(List), CompositeFuture#any(List) and CompositeFuture#join(List) but properly check the generic type <T extends Future<?>>.

See https://github.com/eclipse-vertx/vert.x/pull/3595 why Vert.x doesn't have this.