Dictionary based data structures

Everything has been changed:

• All channels have been merged to one
• All commands are in commands.py
• Voting now allows for the 🅱️ emoji
• Leaderboard is now a single message that is edited
• Users are now stored as a dictionary (see below)

{
    "daily_data": {
        "1234567890": {
            "nick": "Will",
            "submitted": false,
            "voted": false,
            "votes": 1
        },
        "2345678901": {
            "nick": "Dan",
            "submitted": true,
            "voted": true,
            "votes": 0
        }
    },
    "letter_to_user_id": {
        "1234567890": "A",
        "2345678901": "B"
    }
}