Adding more icons and/or allowing users to import custom icons for channel groups.

[ycomiti]

Checklist

• I made sure that there are no existing issues - open or closed - which I could contribute my information to.
• I have read the FAQ and my problem isn't listed.
• I'm aware that this is a request for NewPipe itself and that requests for adding a new service need to be made at NewPipeExtractor.
• I have taken the time to fill in all the required details. I understand that the feature request will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.

Feature description

Adding more icons and/or allowing users to import custom icons for channel groups:

Why do you want this feature?

The default icon set works well for a few generic channel groups, but it lacks variety for more complex groups.

Additional information

No response