Add Command Functionality to Discord Package & Implement Feedback Webhooks (!3)

Co-authored-by: Layla <layla@layla.gg>
Reviewed-on: https://gitea.sumulayla.synology.me/layla/birdbot/pulls/3

discord/user.go

@@ -18,7 +18,8 @@ func NewUser(user *discordgo.User) common.User {
 	}
 
 	return common.User{
-		ID: user.ID,
+		DisplayName: user.Username,
+		ID:          user.ID,
 	}
 }