Feat: Rock Paper Scissors

[brenapp]

Describe the solution you'd like
Allow members to play Rock Paper Scissors through the bot. This is done by DMing the appropriate parties a message to react with their selection to, and revealing once both people have selected. A member challenges another by invocation of the rps command mentioning them. The challenged can accept the challenge by reacting with 🔥

Reference Implementation
https://github.com/MayorMonty/vexbot/blob/f6cf59d8b9f4b235f96cc97e3009c1aebdce37a5/src/commands/rps.ts

[Jay-Madden]

This is a fun idea