Whitelist apps in android

### Steps to reproduce

1. Open settings
2. Click App whitelist button
3. Manually add Apps
4. Apps are now excluded and can show ads

### Expected behavior

Excluded apps should include ads, useful for games
### Actual behavior

There's no option so games that require ad viewing can't be played correctly

Screenshot:

### Your environment

| Description | Value |
| -------------- | ------------ |
| Adguard Content Blocker version:| (e.g. 1.6.10)|
| Browser in use:| (Samsung Interner/Yandex Browser)|
| Filters enabled in Adguard:| (e.g. English, Annoyances)|
| Device model:| (e.g. Google Pixel)|
| Operating system and version:| (e.g. Android 7.1.2)|
| Rooted or not? | (Yes/No) |