Add the ability to manage teams

The config files currently have a multi-table array called `[[teams]]`. This is used right now just for managing who are admins of the org. Ideally, these tables should also maintain actual GitHub teams inside the org.

No file or test is named. Start by tracing how the [[teams]] configuration is parsed and how the tool currently manages organization admins, then identify the GitHub organization synchronization flow. Done means the configuration can maintain actual GitHub teams as well as team administrators, with behavior and edge cases defined.

Written by the indexing model from the issue text.