Ability to set up local rules for non-community servers.

[Jasius]

Hey, I've been on kayaking trip so haven't had time to do a review up until now. Thank you for this thoughtful PR, I've ran through this code once and added some changes(mostly copywriting suggestions)

Also tried running this on a server without community rules set up and it didn't seem to fail gracefuly, just popped off some messaging and errors in the logs.

Going to do more testing now.

I didn't implement that, currently it uses "fetchRules()" but we need something like an interface that fallback to custom rules if it's not a community server: like we need a new command to set up custom rules in the bot, or maybe make the bot use a #rules channel and parse rules from there, need to think more about it

Originally posted by @lost-in-action in #114 (comment)