Add support for slash commands

[eepyeunomia]

Ya have to verify the bot in order to be added to more servers. Please verify thanks.

[matthewzring]

I'm sorry I've taken this long to get back to you.

CyberScores has issues. It needs to be updated to support slash commands very badly.

The scoreboard is getting a (long overdue) API next season, and when that happens, CyberScores will be rewritten entirely to interface with API. I don't know if it makes sense to make other changes before switching to the API.

In the meantime, you can always use commands in DMs with CyberScores via a mention prefix, i.e. @CyberScores ping.