[generator] Improve logging

- more logging for various stages start/finish
- silenced some too repetitive and common warnings (changed to LDEBUG)

Signed-off-by: Konstantin Pastbin <konstantin.pastbin@gmail.com>

generator/final_processor_cities.cpp

@@ -20,6 +20,8 @@ void FinalProcessorCities::Process()
 {
   using namespace feature;
 
+  LOG(LINFO, ("Processing cities..."));
+
   std::mutex mutex;
   auto const & localityChecker = ftypes::IsLocalityChecker::Instance();