mod_http_oauth2: Improve error messages for URI properties Since there are separate validation checks for URI properties, including that they should use https, with better and more specific error reporting. Reverts 'luaPattern' to 'pattern' which is not currently supported by util.jsonschema, but allows anything that retrieves the schema over http to validate against it, should they wish to do so.

# 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