/rules feature

[RiedleroD]

when /rules is sent, the bot should reply with the rules. A few scenarios:

• If person A sends /rules as a reply to message B, the bot should reply with the rules to message B
• If person A sends /rules, the bot should reply to the message from person A

Also, /rules doesn't have any parameters and if any are provided (e.g. a mention), they should be ignored.