Document Data collection/Data Usage Policy

[Ch4ni]

I've done some sniffing on a running instance of slack-term, and determined that the only connections made are to/from the Slack API. It would be extraordinarily helpful to have an official statement made in the README.md, the Wiki, or both that states how slack-term uses the token to connect, and what's done with the data (i.e. stored in memory, discarded on exit, not transmitted to any third parties besides Slack, etc).

It would also be good to have a statement in the wiki under Running slack-term without legacy tokens -> Method #1 that outlines which user data is transmitted, and whether or not any is collected/stored.

Version: any
Installation method: any