Implement removeAllDeliveredNotifications.

[amazingmarvin]

This function clears delivered notifications, but not scheduled local notifications. Since it's in react-native's PushNotificationIOS, adding it to react-native-push-notification brings us closer to feature parity. And this is a simple, but important one. See RN Docs.

The following code can be used to test this functionality:

import {
  AppState,
} from "react-native";

import PushNotification from "react-native-push-notification";

function clearNotifications() {
  const { currentState } = AppState;

  if (currentState === "active") {
    PushNotification.removeAllDeliveredNotifications();
  }
}

AppState.addEventListener("change", clearNotifications);
setTimeout(clearNotifications, 0);

This makes notifications clear on startup and when the app enters foreground. When you open the app, all notifications for the app in the notification center should disappear. To further test it, schedule a notification, then put the app in the background and then the foreground again. The scheduled notification should appear anyway. Canceling scheduled local notifications was a blocker for my app before this PR.

This PR addresses one point in #427. I may implement the other new features if I find a need for them.

[dnlsilva]

@zo0r merge these pull request, and release a new version.

[RichardNTran]

please merge it now.

[samaneh-kamalian]

please merge it.