Push Notification permissions inconsistency

[TimofeyBurak]

Description

Push-notifications permissions are requested with hardcoded options, even though the options should probably be defined by PushNotificationService functionality:
https://github.com/Softeq/XToolkit.WhiteLabel/blob/master/Softeq.XToolkit.Permissions.iOS/PermissionsService.cs#L70-L78

Also, it seems like our implementation of checking push-notification permissions might have an issue: we take into account specific settings, not only authorization status
https://github.com/Softeq/XToolkit.WhiteLabel/blob/master/Softeq.XToolkit.Permissions.iOS/PermissionsService.cs#L54-L68
One thing is that settings are hardcoded, which is not good - again, seems like PushNotificationService should decide which settings are actually required. The second is that the logic itself might be a bit incorrect - if user grants permission for alert+sound, for instance, and then disables sounds in settings, then our implementation would say that notification permissions are denied, although it is not true and notifications would still be received and shown to user.

Steps to Reproduce

1. Request push notification permission using IPermissionsManager.CheckWithRequestAsync<NotificationsPermission>()
2. Use PushNotificationService to handle push notifications

Expected Behavior

PushNotificationService has all required options authorized

Actual Behavior

Only Alert and Sound options are authorized always

Possible Fix

I would suggest to remove push-notification permissions from the Permissions project and implement it in the PushNotifications project (as a part of IPushNotificationService, or as a separate service?), and also rework check permissions logic.

Basic Information

• Version with issue: XToolkit.Permissions 2.1.0, XToolkit.PushNotifications 1.0.1

[TimofeyBurak]

Related to #500