Role Assignment

[keenanbuckley]

• Add the ability for users to self assign roles
• Popular implementations of this set up emoji reactions to a post by the bot listing the available roles.
• When a user gives a reaction, the bot is triggered to assign them the corresponding role
• When they remove the reaction, the bot removes that role
• Should probably use SQL or MongoDB to store data (see Implement the aiosqlite library so that our bot can store data in an asynchronous way #4) if we don't just hardcode it or store a prebuilt json in static