[Feature request] Add Whitelist option to "filter by channels" content filter

[hh1599]

Checklist

• [x] I have tested the latest 5.0 beta version, and it doesn't have this feature.
• [x] I have searched for existing issues (open and closed) and confirmed this feature hasn't been requested before
• [x] I believe this feature request will benefit more than 10% of users, not just myself

Feature Description

Hi, thank you for making this app. I have been using newpipe for years and didnt realize there was a better version available.

I have been looking for a youtube app that I can put on my kids tablet to only allow them to watch youtube channels that I approve (unbelievably, this is impossible using google's parental controls).

Pipepipe is so close with a content filter and channel blocker. Would it be possible to have a whitelist option as well? The ability to lock the settings menu with a pin code would also be awesome.