inform gateway-selector service if we're manually overriding gateway selection
the idea is to send a parameter in the query just to inform the service that we're manually overriding the options.
this only be useful after getmyip#9 has been implemented - documentation of the api should be updated accordingly.
it does not matter if the mechanism is implemented in the android client beforehand.
the desktop issue, for coordination: bitmask-vpn#373