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.

src/memory/memory.py

@@ -853,7 +853,7 @@ class Memory(object):
         return self.params.getStringParamA(name, category, attr, profile_key)
 
     def getParamA(self, name, category, attr="value", profile_key=C.PROF_KEY_NONE):
-        return self.params.getParamA(name, category, attr, profile_key)
+        return self.params.getParamA(name, category, attr, profile_key=profile_key)
 
     def asyncGetParamA(self, name, category, attr="value", security_limit=C.NO_SECURITY_LIMIT, profile_key=C.PROF_KEY_NONE):
         return self.params.asyncGetParamA(name, category, attr, security_limit, profile_key)