RTC: add notion of 'quality' for different time sources

Allow use of mesh based time until a GPS time arrives

src/gps/UBloxGPS.cpp

@@ -152,7 +152,7 @@ bool UBloxGPS::lookForTime()
         t.tm_mon = ublox.getMonth(0) - 1;
         t.tm_year = ublox.getYear(0) - 1900;
         t.tm_isdst = false;
-        perhapsSetRTC(t);
+        perhapsSetRTC(RTCQualityGPS, t);
         return true;
     }