check system_config to determine if auth local

With authz_local_resources set to true, calls placed to local resources will now consume an inbound trunk.

Noted that this was set %%TODO.
So the trick here (and the reason that it was still a TODO) is you really should be checking for node specific settings. 

IE: when this request is issued it will look for whistle_apps@somenode.authz_local_resources then default.authz_local_resources.

What needs to happen is j5_request should store and provide access to <<"Node">> from the AMQP authz request.  This would be the ecallmgr node that has issued the request and subsequently  where we should look for node specific settings.  whapps_config has get_is_false/4 which will let you override the node used when checking for the key.  The intent would be to request the following config from a whapps node:

ecallmgr@someothernode.authz_local_resources and if not found default.authz_local_resources

The reason being, it is currently possible to deploy this in such a way that one group of freeswitch/ecallmgr servers does authz_local_resources while another (different zone) does not.  Since they share the same jonny5 nodes this would not support such a configuration.

Let me know if that makes sense, thanks!