v0.5.0: Poise framework and slash commands

Many changes and new features in this version, including the adoption of Discord's integrated slash commands using Poise.

• Most (99%) special characters in names will now correctly link to the BTN page. Please submit an issue if you find one that doesn't. If your name has a space in it, you'll have to replace it with "00" when using /about_name (like /about_name Mary00Ann Van00Buren). Working on an alternative.
• about is now about_name. It also now only displays the response to you if you use the slash command version. Feedback is welcome on this.
• New help command added. If you want to know more about the available commands or about the usage of each command, try /help_rnc or /help_rnc name|about_name.
• Fancy slash commands are now fully operational. Try it out with /name instead of ~name. The tilde option will be removed eventually.
• Chaotic mode added. You may have noticed that I've implemented what I think is a sensible default of choosing a first and last name from the same culture/language. If you don't want that, enter chaotic for the mode option with /name. Godspeed, Thranduil Papadopoulos.