Create initial team command documentation

[rwblickhan]

Create a document in docs/ (similar to the one created for #25) that lists the various options/help strings/etc that we will implement for MVP for the @rocket team command.

In particular, we will want to match the functionality of the current @rocket edit-team, @rocket remove-user, @rocket view-team, @rocket add-team, @rocket add-user, @rocket remove-team, and @rocket teams commands (but hopefully with better/more consistent names!). These should probably all be implemented as subcommands to the core @rocket team command (similar to how user commands are being done).