mod_client_management: Add support for revocation of clients (when possible) We decided to keep the unified listing of "clients", which includes both SASL2 clients and OAuth grants, etc. To a user, or someone wanting to manage what can access their account, they are largely equivalent. To accomplish this technically, we add a prefix to the id to state what type it really is.

# Introduction

This module sends a [version query][xep0092] to clients when they
connect, and logs the response, allowing statistics of client usage to
be recorded.

Note that since this is per connection, there will be a bias towards
mobile clients on bad connections.

## Example

    info    Running Running Swift version 4.0