[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/raw_generator.cpp

@@ -265,6 +265,7 @@ bool RawGenerator::GenerateFilteredFeatures()
   while (!isEnd);
 
   LOG(LINFO, ("OSM source input was processed."));
+  LOG(LINFO, ("Finishing translators..."));
   if (!translators.Finish())
     return false;