Allow DMs from CPP CS server members

As a user, I want to be able to grade my resume through private DMs with the bot.

Not necessary since there is a private option for the grading command, which sends the resume critique through a DM. The option to just use the bot in a DM is still nice though.

Documentation for DMChannel object:
https://old.discordjs.dev/#/docs/discord.js/main/class/DMChannel