feat(discord): Added /balance {give,set} commands

- Also, you cannot /answer to unpublished quest
- Also, changed /scoreboard to print name instead of mentioning
- Also, made --config an option, defaulting to "cfg/config.toml"

discord/src/commands/answer.rs

@@ -28,7 +28,9 @@ pub async fn answer(
     }
 
     let quests = ctx.data().config.load_quests();
-    let Some(quest) = quests.iter().find(|q| q.id == quest_id) else {
+    let Some(quest) = quests.iter()
+        .filter(|q| q.public)
+        .find(|q| q.id == quest_id) else {
         return Err(Error::QuestNotFound(quest_id));
     };