Weight required stars for starboard from origin channel

[patrickklaeren]

Currently we have a hardcoded value for the minimum amount of stars required for a message to be sent to a starboard channel.

It has been suggested, by @tannergooding, that we allow for configurable star thresholds based on if the channel is on/off topic.

There are two aspects to this case: make the threshold configurable, i.e. unhardcode https://github.com/discord-csharp/MODiX/blob/master/Modix.Services/Starboard/StarboardService.cs#L157-L158

The other aspect being a concept to allow for per-channel configuration of the amount of stars required for a message to be sent to starboard, favoring on topic channels.