Add structures

[CleverSource]

This PR will introduce structures to the library. Allowing for methods to be attached to data types such as channels (example below).

bot:on("channelCreate", function(channel)
    channel:sendMessage(`This channel named \`{channel.name}\` is cool!`)
end :: typeof(bot.events.channelCreate))

vs.

bot:on("channelCreate", function(channel)
    bot.rest:sendMessage({
        content = `This channel named \`{channel.name}\` is cool!`
    })
end :: typeof(bot.events.channelCreate))