core (common): added a notifications counter on ContactButton and use it in JidSelector: A notifications counter is drawned above avatar if `nofifs` key is present and not empty in `data`. This is used in JidSelector to show counter when necessary with opened chats.

<intent-filter>
    <action android:name="android.intent.action.SEND" />
    <category android:name="android.intent.category.DEFAULT" />
    <data android:mimeType="*/*" />
</intent-filter>