request: add option to post suggestion responses in new messages

[kyranet]

The new option in /config would allow users to customise whether or not Iriss should send the responses in a separate message.

The new messages would look like they currently do but "detached", respecting all the existing options, and would set the reply field to have an easy way to find the original post.

Ref: https://discord.com/channels/254360814063058944/401142717758963724/1225843799520186369