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.

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summary: Log a message once per minute
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This module sends `-- MARK --` to the log once per minute. This may be
useful to give a sense of how busy the server is or see that logging and
timers are still working.