Refactor to use the command pattern for better-organized code

[stillgreenmoss]

We think that using the command pattern to execute user-issued commands in Pairing Bot might make the codebase cleaner and more readable.

Any recurser, though especially recursers currently in batch, should message me or @parsn1psoup if they'd like to work on this.

[stillgreenmoss]

@parsn1psoup @RobertXu did someone do this or is this still open?

[parsn1psoup]

@dimriver I didn't and I'm not aware that someone else did