plugin ip, params: plugin IP discovery, first draft: - a dedicated plugin now manage IP discovery, for now it uses external website, but it should implement XEP-0279 soon - a permission is requested to user for calling an external website. Once the permission is granted (it's global), it is not asked anymore. - the ip is discovered on demand, and cache is kept for the session. - memory.params.getParamA has a new parameter use_default, which allow to get None when a parameter is not set, instead of the default value. This allow to detected when we need to do the first permission request. memory.getParamA don't have this parameter.