integrate utz, use DST-aware time zones instead of bare offsets

watch-library/shared/watch/watch_utility.c

@@ -315,11 +315,3 @@ uint32_t watch_utility_offset_timestamp(uint32_t now, int8_t hours, int8_t minut
     new += seconds;
     return new;
 }
-
-uint8_t days_in_month(uint8_t month, uint16_t year) {
-    static const uint8_t days_in_month[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
-    uint8_t days = days_in_month[month - 1];
-    if (month == 2 && is_leap(year))
-        days += 1;
-    return days;
-}