add package for sending push notifications

[chrisK00]

usage

        var notification = new Plugin.LocalNotification.NotificationRequest()
        {
            NotificationId = Random.Shared.Next(),
            Title = "Netflix is due in 2 days",
            CategoryType = Plugin.LocalNotification.NotificationCategoryType.Reminder,
        };

        var hasEnabledNotifications = await Plugin.LocalNotification.LocalNotificationCenter.Current.AreNotificationsEnabled();
	if (!hasEnabledNotifications)
	{
	    await LocalNotificationCenter.Current.RequestNotificationPermission();
	}

        Plugin.LocalNotification.LocalNotificationCenter.Current.Show(notification);