wallet: fast rescan: show log message for every non-skipped block

For that purpose, a new logging category BCLog::SCAN is introduced.

src/logging.cpp

@@ -181,6 +181,7 @@ const CLogCategoryDesc LogCategories[] =
     {BCLog::UTIL, "util"},
     {BCLog::BLOCKSTORE, "blockstorage"},
     {BCLog::TXRECONCILIATION, "txreconciliation"},
+    {BCLog::SCAN, "scan"},
     {BCLog::ALL, "1"},
     {BCLog::ALL, "all"},
 };
@@ -283,6 +284,8 @@ std::string LogCategoryToStr(BCLog::LogFlags category)
         return "blockstorage";
     case BCLog::LogFlags::TXRECONCILIATION:
         return "txreconciliation";
+    case BCLog::LogFlags::SCAN:
+        return "scan";
     case BCLog::LogFlags::ALL:
         return "all";
     }